We see a completely new mode for the Eye in the Dark Dimension. With a flourish of his right hand over his left forearm, a band of green lines begin orbiting his forearm just below his wrist. (Another orbits just below his elbow, just off-camera in the animated gif.) The band signals that Strange has set this point in time as a “save point,” like in a video game. From that point forward, when he dies, time resets and he is returned here, alive and well, though he and anyone else in the loop is aware that it happened.
In the scene he’s confronting a hostile god-like creature on its own mystical turf, so he dies a lot.
An interesting moment happens when Strange is hopping from the blue-ringed planetoid to the one close to the giant Dormammu face. He glances down at his wrist, making sure that his savepoint was set. It’s a nice tell, letting us know that Strange is a nervous about facing the giant, Galactus-sized primordial evil that is Dormammu. This nervousness ties right into the analysis of this display. If we changed the design, we could put him more at ease when using this life-critical interface.
The initiating gesture doesn’t read as “set a savepoint.” This doesn’t show itself as a problem in this scene, but if the gesture did have some sort of semantic meaning, it would make it easier for Strange to recall and perform correctly. Maybe if his wrist twist transitioned from moving splayed fingers to his pointing with his index finger to his wrist…ok, that’s a little too on the nose, so maybe…toward the ground, it would help symbolize the here & now that is the savepoint. It would be easier for Strange to recall and feel assured that he’d done the right thing.
I have questions about the extents of the time loop effect. Is it the whole Dark Dimension? Is it also Earth? Is it the Universe? Is it just a sphere, like the other modes of the Eye? How does he set these? There’s not enough information in the movie to backworld this, but unless the answer is “it affects everything” there seems to be some variables missing in the initiating gesture.
But where the initiating gesture doesn’t appear to be a problem in the scene, the wrist-glance indicates that the display is. Note that, other than being on the left forearm instead of the right, the bands look identical to the ones in the Tibet and Hong Kong modes. (Compare the Tibet screenshot below.) If Strange is relying on the display to ensure that his savepoint was set, having it look identical is not as helpful as it would be if the visual was unique. “Wait,” he might think, “Am I in the right mode, here?”
In a redesign, I would select an animated display that was not a loop, but an indication that time was passing. It can’t be as literal as a clock of course. But something that used animation to suggest time was progressing linearly from a point. Maybe something like the binary clock from Mission to Mars (see below), rendered in the graphic language of the Eye. Maybe make it base-3 to seem not so technological.
Seeing a display that is still, on invocation—that becomes animated upon initialization—would mean that all he has to do is glance to confirm the unique display is in motion. “Yes, it’s working. I’m in the Groundhog Day mode, and the savepoint is set.”
In the priorthreeposts, I’ve discussed the goods-and-bads of the Eye of Agamotto in the Tibet mode. (I thought I could squeeze the Hong Kong and the Dark Dimension modes into one post, but turns out this one was just too long. keep reading. You’ll see.) In this post we examine a mode that looks like the Tibet mode, but is actually quite different.
Hong Kong mode
Near the film’s climax, Strange uses the Eye to reverse Kaecilius’ destruction of the Hong Kong Sanctum Sanctorum (and much of the surrounding cityscape). In this scene, Kaecilius leaps at Strange, and Strange “freezes” Kaecilius in midair with the saucer. It’s done more quickly, but similarly to how he “freezes” the apple into a controlled-time mode in Tibet.
But then we see something different, and it complicates everything. As Strange twists the saucer counterclockwise, the cityscape around him—not just Kaecilius—begins to reverse slowly. (And unlike in Tibet, the saucer keeps spinning clockwise underneath his hand.) Then the rate of reversal accelerates, and even continues in its reversal after Strange drops his gesture and engages in a fight with Kaecilius, who somehow escapes the reversing time stream to join Strange and Mordo in the “observer” time stream.
So in this mode, the saucer is working much more like a shuttle wheel with no snap-back feature.
A shuttle wheel, as you’ll recall from the first post, doesn’t specify an absolute value along a range like a jog dial does. A shuttle wheel indicates a direction and rate of change. A little to the left is slow reverse. Far to the left is fast reverse. Nearly all of the shuttle wheels we use in the real world have snap-back features, because if you were just going to leave it reversing and pay attention to something else, you might as well use another control to get to the absolute beginning, like a jog dial. But, since Strange is scrubbing an endless “video stream,” (that is, time), and he can pull people and things out of the manipulated-stream and into the observer-stream and do stuff, not having a snap-back makes sense.
For the Tibet mode I argued for a chapter ring to provide some context and information about the range of values he’s scrubbing. So for shuttling along the past in the Hong Kong mode, I don’t think a chapter ring or content overview makes sense, but it would help to know the following.
The rate of change
Direction of change
Timedate difference from when he started
In the scene that information is kind of obvious from the environment, so I can see the argument for not having it. But if he was in some largely-unchanging environment, like a panic room or an underground cave or a Sanctum Sanctorum, knowing that information would save him from letting the shuttle go too far and finding himself in the Ordovician. A “home” button might also help to quickly recover from mistakes. Adding these signals would also help distinguish the two modes. They work differently, so they should look different. As it stands, they look identical.
He still (probably) needs future branches
Can Strange scrub the future this way? We don’t see it in the movie. But if so, we have many of the same questions as the Tibet mode future scrubber: Which timeline are we viewing & how probable is it? What other probabilities exist and how does he compare them? This argues for the addition of the future branches from that design.
Selecting the mode
So how does Strange specify the jog dial or shuttle wheel mode?
One cop-out answer is a mental command from Strange. It’s a cop-out because if the Eye responds to mental commands, this whole design exercise is moot, and we’re here to critique, practice, and learn. Not only that, but physical interfaces are more cinemagenic, so better to make a concrete interaction for the film.
You might think we could modify the opening finger-tut (see the animated gif, below). But it turns out we need that for another reason: specifying the center and radius-of-effect.
Center and radius-of-effect
In Tibet, the Eye appears to affect just an apple and a tome. But since we see it affecting a whole area in Hong Kong, let’s presume the Eye affects time in a sphere. For the apple and tome, it was affecting a small sphere that included the table, too, it’s just that table didn’t change in the spans of time we see. So if it works in spheres, how is the center and the radius of the sphere set?
Let’s say the Eye does some simple gaze monitoring to find the salient object at his locus of attention. Then it can center the effect on the thing and automatically set the radius of effect to the thing’s size across likely-to-be scrubbed extents. In Tibet, it’s easy. Apple? Check. Tome? Check. In Hong Kong, he’s focusing on the Sanctum, and its image recognition is smart enough to understand the concept of “this building.”
But the Hong Kong radius stretches out beyond his line of sight, affecting something with a very vague visual and even conceptual definition, that is, “the wrecked neighborhood.” So auto-setting these variables wouldn’t work without reconceiving the Eye as a general artificial intelligence. That would have some massive repercussions throughout the diegesis, so let’s avoid that.
If it’s a manual control, how does he do it? Watch the animated gif above carefully and see he’s got two steps to the “turn Eye on” tut: opening the eye by making an eye shape, and after the aperture opens, spreading his hands apart, or kind of expanding the Eye. In Tibet that spreading motion is slow and close. In Hong it’s faster and farther. That’s enough evidence to say the spread*speed determines the radius. We run into the scales problem of apple-versus-neighborhood that we had in determining the time extents, but make it logarithmic and add some visual feedback and he should be able to pick arbitrary sizes with precision.
So…back to mode selection
So if we’re committing the “turn on” gesture to specifying the center-and-radius, the only other gesture left is the saucer creation. For a quick reminder, here’s how it works in Tibet.
Since the circle works pretty well for a jog dial, let’s leave this for Tibet mode. A contrasting but related gesture would be to have Strange hold his right hand flat, in a sagittal plane, with the palm facing to his left. (See an illustration, below.) Then he can tilt his hand inside the saucer to reverse or fast forward time, and withdraw his hand from the saucer graphic to leave time moving at the adjusted rate. Let the speed of the saucer indicate speed of change. To map to a clock, tilting to the left would reverse time, and tilting to the right would advance it.
The yank out
There’s one more function we see twice in the Hong Kong scene. Strange is able to pull Mordo and Wong from the reversing time stream by thrusting the saucer toward them. This is a goofy choice of a gesture that makes no semantic sense. It would make much more sense for Strange to keep his saucer hand extended, and use his left hand to pull them from the reversing stream.
So one of the nice things about this movie interface, is that while it doesn’t hold up under the close scrutiny of this blog, the interface to the Eye of Agamotto works while watching the film. Audience sees the apple happen, and gets that gestures + glowing green circle = adjusting time. For that, it works.
That said, we can see improvements that would not affect the script, would not require much more of the actors, and not add too much to post. It could be more consistent and believable.
But we’re not done yet. There’s one other function shown by the Eye of Agamotto when Strange takes it into the Dark Dimension, which is the final mode of the Eye, up next.
A major problem with the use of the Eye is that it treats the past and the future similarly. But they’re not the same. The past is a long chain of arguably-knowable causes and effects. So, sure, we can imagine that as a movie to be scrubbed.
But the future? Not so much. Which brings us, briefly, to this dude.
If we knew everything, Pierre-Simon Laplace argued in 1814, down to the state of every molecule, and we had a processor capable, we would be able to predict with perfect precision the events of the future. (You might think he’s talking about a computer or an AI, but in 1814 they used demons for their thought experiments.) In the two centuries since, there have been several major repudiations of Laplace’s demon. So let’s stick to the near-term, where there’s not one known future waiting to happen, but a set of probabilities. That means we have to rethink what the Eye shows when it lets Strange scrub the future.
Note that in the film, the “future” of the apple shown to Strange was just a likelihood, not a fact. The Eye shows it being eaten. In the actual events of the film, after the apple is set aside:
Strange repairs the tome
Mordo and Wong interrupt Strange
They take him into the next room for some exposition
The Hong Kong sanctum portal swings open
Kaecilius murders a redshirt
Kaecilius explodes Strange into the New York sanctum
Then for the next 50 minutes, The Masters of Mysticism are scrambling to save the world. I doubt any of them have time to while away in a library, there to discover an abandoned apple with a bite taken out of it, and decide—staphylococcus aureus be damned—a snack’s a snack. No, it’s safe to say the apple does not get eaten.
So the Eye gets the apple wrong, but it showed Strange that future as if it were a certainty. That’s a problem. Sure, when asked about the future, it ought to show something, but better would be to…
Indicate somewhere that what is being displayed is one of a set of possibilities
Provide options to understand the probability distribution among the set
Explore the alternates
Be notified when new data shifts the probability distribution or inserts new important possibilities
So how to display probabilities? There are lots of ways, but I am most fond of probability tree diagrams. In nerd parlance, this is a unidirectional graph where the nodes are states and the lines are labeled for probabilities. In regular language they look like sideways two-dimensional trees. See an example below from mathisfun.com. These diagrams seem to me a quick way to understand branching possibilities. (I couldn’t find any studies giving me more to work on than “seem to me”.)
In addition to being easy to understand, they afford visual manipulation. You can work branching lines around an existing design.
Now if we were actually working out a future-probabilities gestural scrubber attached to the Eye of Agamotto saucer, we’d have a whole host of things to get into next, like designing…
A compact but informative display that signals the relative probabilities of each timeline
The mechanism for opening that display so probabilities can be seen rather than read
Labels so Strange wouldn’t have to hunt through all of them for the thing of interest (or some means of search)
A selection process for picking the new timeline
A comparison mode
A means of collapsing the display to return to scrub mode
A you-are-here signal in the display to indicate the current timeline
Which is a big set of design tasks for a hobbyist website. Fortunately for us, Strange only deals with a simple, probable (but wrong) scenario of the apple’s future as an illustration for the audience of what the Eye can do; and he only deals with the past of the tome. So while we could get into all of the above, it’s most expedient just to resolve the first one for the scene and tidy up the interface as it helps illustrate a well-thought-out and usable world.
Below I’ve drafted up an extension of my earlier conceptual diagram. I’ve added a tree to the future part of the chapter ring, using some dots to indicate the comparative likelihood of each branch. This could be made more compact, and might be good to put on a second z-axis layer to distinguish it from the saucer, but again: conceptual diagram.
If this were implemented in the film, we would want to make sure that the probability tree begins to flicker right before Wong and Mordo shut him down, as a nod to the events happening off screen with Kaecilius that are changing those futures. This would give a clue that the Eye is smartly keeping track of real-world events and adjusting its predictions appropriately.
These changes would make the Eye more usable for Strange and smart as a model for us.
Twist ending: This is a real problem we will have to solve
I skipped those design tasks for this comp, but we may not be able to avoid those problems forever. As it turns out, this is not (just) an idle, sci-fi problem. One of the promises of assistive AI is that it will be giving its humans advice, based on predictive algorithms, which will be a set of probabilistic scenarios. There may be an overwhelmingly likely next scenario, but there may also be several alternatives that users will need to explore and understand before deciding the best strategy. So, yeah, an exercise for the reader.
Wrapping up the Tibet Mode
So three posts is not the longest analysis I’ve done, bit it was a lot. In recap: Gestural time scrubbing seems like a natural interaction mapped well to analog clocks. The Eye’s saucer display is cool, but insufficient. We can help Strange much more by adding an events-based chapter ring detailing the facts of the past and the probabilities of the future.
Alas. We’re not done yet. As you’ll recall from the intro post, there are two other modes: The Hong Kong and Dark Dimension modes. Let’s next talk the Hong Kong mode, which is like the Tibet mode, but different.
Without a display, the Eye asks Strange to do all the work of exploring the range of values available through it to discover what is of interest. (I am constantly surprised at how many interfaces in the real world repeat this mistake.) We can help by doing a bit of “pre-processing” of the information and provide Strange a key to what he will find, and where, and ways to recover exactly where interesting things happen.
To do this, we’ll add a ring outside the saucer that will stay fixed relative to the saucer’s rotation and contain this display. Since we need to call this ring something, and we’re in the domain of time, let’s crib some vocabulary from clocks. The fixed ring of a clock that contains the numbers and minute graduations is called a chapter ring. So we’ll use that for our ring, too.
What chapter ring content would most help Strange?
Good: A time-focused chapter ring
Both the controlled-extents and the auto-extents shown in the prior post presume a smooth display of time. But the tome and the speculative meteorite simply don’t change much over the course of their existence. I mean, of course they do, with the book being pulled on and off shelves and pages flipped, and the meteorite arcing around the sun in the cold vacuum of space for countless millennia, but the Eye only displays the material changes to an object, not position. So as far as the Eye is concerned, the meteoroid formed, then it stays the same for most of its existence, then it has a lot of activity as it hits Earth’s atmosphere and slams into the planet.
A continuous display of the book shows little of interest for most of its existence, with a few key moments of change interspersed. To illustrate this, lets make up some change events for the tome.
Now let’s place those along an imaginary timeline. Given the Doctor Strange storyline, Page Torn would more likely be right next to Now, but making this change helps us explore a common boredom problem, see below. OK. Placing those events along a timeline…
And then, wrapping that timeline around the saucer. Much more art direction would have to happen to make this look thematically like the rest of the MCU magic geometries, but following is a conceptual diagram of how it might look.
On the outside of the saucer is the chapter ring with the salient moments of change called out with icons (and labels). At a glance Strange would know where the fruitful moments of change occur. He can see he only has to turn his hand about 5° to the left to get to the spot where the page was ripped out.
Already easier on him, right? Some things to note.
The chapter ring must stay fixed relative to the saucer to work as a reference. Imagine how useless a clock would be if its chapter ring spun in concert with any of its hands. The center can still move with his palm as the saucer does.
The graduations to the left and right of “now” are of a different density, helping Strange to understand that past and future are mapped differently to accommodate the limits of his wrist and the differing time frames described.
When several events occur close together in time, they could be stacked.
Having the graduations evenly spaced across the range helps answer roughly when each change happened relative to the whole.
The tome in front of him should automatically flip to spreads where scrubbed changes occur, so Strange doesn’t have to hunt for them. Without this feature, if Strange was trying to figure out what changed, he would have to flip through the whole book with each degree of twist to see if anything unknown had changed.
Better: A changes-focused chapter ring
If, as in this scene, the primary task of using the Eye is to look for changes, a smooth display of time on the chapter ring is less optimal than a smooth display of change. (Strange doesn’t really care when the pages were torn. He just wants to see the state of the tome before that moment.) Distribute the changes evenly around the chapter ring, and you get something like the following.
This display optimizes for easy access to the major states of the book. The now point is problematic since the even distribution puts it at the three o’clock point rather than the noon, but what we buy in exchange is that the exact same precision is required to access any of the changes and compare them. There’s no extra precision needed to scrub between the book made and the first stuff added moments. The act of comparison is made simpler. Additionally, the logarithmic time graduations help him scrub detail near known changes and quickly bypass the great stretches of time when nothing happens. By orienting our display around the changes, the interesting bits are made more easy to explore, and the boring bits are more easy to bypass.
In my comp, more white areas equal more time. Unfortunately, this visual design kind of draws attention to the empty stretches of time rather than the moments of change, so would need more attention; see the note above about needing a visual designer involved.
So…the smooth time and the distributed events display each has its advantages over the other, but for the Tibet scene, in which he’s looking to restore the lost pages of the tome, the events-focused chapter ring gets Strange to the interesting parts more confidently.
This is one of those sci-fi interactions that seems simple when you view it, but then on analysis it turns out to be anything but. So set aside some time, this analysis will be one of the longer ones even broken into four parts.
The Eye of Agamotto is a medallion that (spoiler) contains the emerald Time Infinity Stone, held on by a braided leather strap. It is made of brass, about a hand’s breadth across, in the shape of a stylized eye that is covered by the same mystical sigils seen on the rose window of the New York Sanctum, and the portal door from Kamar-Taj to the same.
We see the Eye used in three different places in the film, and in each place it works a little differently.
The Tibet Mode
The Hong Kong Modes
The Dark Dimension Mode
The Tibet Mode
When the film begins, the Eye is under the protection of the Masters of the Mystic Arts in Kamar-Taj, where there’s even a user manual. Unfortunately it’s in mysticalese (or is it Tibetan? See comments) so we can’t read it to understand what it says. But we do get a couple of full-screen shots. Are there any cryptanalysists in the readership who can decipher the text?
The power button
Strange opens the old tome and reads “First, open the eye of Agamotto.” The instructions show him how to finger-tut a diamond shape with both hands and spread them apart. In response the lid of the eye opens, revealing a bright green glow within. At the same time the components of the sigil rotate around the eye until they become an upper and lower lid. The green glow of this “on state” persists as long as Strange is in time manipulation mode.
Once it’s turned on, he puts the heels of his palms together, fingers splayed out, and turns them clockwise to create a mystical green circle in the air before him. At the same time two other, softer green bands spin around his forearm and elbow. Thrusting his right hand toward the circle while withdrawing his left hand behind the other, he transfers control of the circle to just his right hand, where it follows the position of his palm and the rotation of his wrist as if it was a saucer mystically glued there.
Then he can twist his wrist clockwise while letting his fingers close to a fist, and the object on which he focuses ages. When he does this to an apple, we see it with progressively more chomps out of it until it is a core that dries and shrivels. Twisting his wrist counter clockwise, the focused object reverses aging, becoming younger in staggered increments. With his middle finger upright, the object reverts to its “natural” age.
Pausing and playing
At one point he wants to stop practicing with the apple and try it on the tome whose pages were ripped out. He relaxes his right hand and the green saucer disappears, allowing him to manipulate it and a tome without changing their ages. To reinstate the saucer, he extends his fingers out and gives his hand a shake, and it fades back into place.
Tibet Mode Analysis: The best control type
The Eye has a lot of goodness to it. Time has long been mapped to circles in sun dials and clock faces, so the circle controls fit thematically quite well. The gestural components make similar sense. The direction of wrist twist coincides with the movement of clock hands, so it feels familiar. Also we naturally look at and point at objects of focus, so using the extended arm gesture combined with gaze monitoring fits the sense of control. Lastly, those bands and saucers look really cool, both mystical in pattern and vaguely technological with the screen-green glow.
Readers of the blog know that it rarely just ends after compliments. To discuss the more challenging aspects of this interaction with the Eye, it’s useful to think of it as a gestural video scrubber for security footage, with the hand twist working like a jog wheel. Not familiar with that type of control? It’s a specialized dial, often used by video editors to scroll back and forth over video footage, to find particular sequences or frames. Here’s a quick show-and-tell by YouTube user BrainEatingZombie.
Is this the right kind of control?
There are other options to consider for the dial types of the Eye. What we see in the movie is a jog dial with hard stops, like you might use for an analogue volume control. The absolute position of the control maps to a point in a range of values. The wheel stops at the extents of the values: for volume controls, complete silence on one end and max volume at the other.
But another type is a shuttle wheel. This kind of dial has a resting position. You can turn it clockwise or counterclockwise, and when you let go, it will spring back to the resting position. While it is being turned, it enacts a change. The greater the turn, the faster the change. Like a variable fast-forward/reverse control. If we used this for a volume control: a small turn to the left means, “Keep lowering the volume a little bit as long as I hold the dial here.” A larger turn to the left means, “Get quieter faster.” In the case of the Eye, Strange could turn his hand a little to go back in time slowly, and fully to reverse quickly. This solves some mapping problems (discussed below) but raises new issues when the object just doesn’t change that much across time, like the tome. Rewinding the tome, Strange would start slow, see no change, then gradually increase speed (with no feedback from the tome to know how fast he was going) and suddenly he’d fly way past a point of interest. If he was looking for just the state change, then we’ve wasted his time by requiring him to scroll to find it. If he’s looking for details in the moment of change, the shuttle won’t help him zoom in on that detail, either.
There are also free-spin jog wheels, which can specify absolute or relative values, but since Strange’s wrist is not free-spinning, this is a nonstarter to consider. So I’ll make the call and say what we see in the film, the jog dial, is the right kind of control.
So if a jog dial is the right type of dial, and you start thinking of the Eye in terms of it being a video scrubber, it’s tackling a common enough problem: Scouring a variable range of data for things of interest. In fact, you can imagine that something like this is possible with sophisticated object recognition analyzing security footage.
The investigator scrubs the video back in time to when the Mona Lisa, which since has gone missing, reappears on the wall.
Show me what happened—across all cameras in Paris—to that priceless object…
She points at the painting in the video.
So, sure, we’re not going to be manipulating time any…uh…time soon, but this pattern can extend beyond magic items a movie.
The scrubber metaphor brings us nearly all the issues we have to consider.
What are the extents of the time frame?
How are they mapped to gestures?
What is the right display?
What about the probabilistic nature of the future?
What are the extents of the time frame?
Think about the mapping issues here. Time goes forever in each direction. But the human wrist can only twist about 270 degrees: 90° pronation (thumb down) and 180° supination (thumb away from the body, or palm up). So how do you map the limited degrees of twist to unlimited time, especially considering that the “upright” hand is anchored to now?
The conceptually simplest mapping would be something like minutes-to-degree, where full pronation of the right hand would go back 90 minutes and full supination 2 hours into the future. (Noting the weirdness that the left hand would be more past-oriented and the right hand more future-oriented.) Let’s call this controlled extents to distinguish it from auto-extents, discussed later.
What if -90/+180 minutes is not enough time to entail the object at hand? Or what if that’s way too much time? The scale of those extents could be modified by a second gesture, such as the distance of the left hand from the right. So when the left hand was very far back, the extents might be -90/+180 years. When the left hand was touching the right, the extents might be -90/+180 milliseconds to find detail in very fast moving events. This kind-of backworlds the gestures seen in the film.
That’s simple and quite powerful, but doesn’t wholly fit the content for a couple of reasons. The first is that the time scales can vary so much between objects. Even -90/+180 years might be insufficient. What if Strange was scrubbing the timeline of a Yareta plant (which can live to be 3,000 years old) or a meteorite? Things exist in greatly differing time scales. To solve that you might just say OK, let’s set the scale to accommodate geologic or astronomic time spans. But now to select meaningfully between the apple and the tome his hand must move mere nanometers and hard for Strange to get right. A logarithmic time scale to that slider control might help, but still only provides precision at the now end of the spectrum.
If you design a thing with arbitrary time mapping you also have to decide what to do when the object no longer exists prior to the time request. If Strange tried to turn the apple back 50 years, what would be shown? How would you help him elegantly focus on the beginning point of the apple and at the same time understand that the apple didn’t exist 50 years ago?
So letting Strange control the extents arbitrarily is either very constrained or quite a bit more complicated than the movie shows.
Could the extents be automatically set per the focus?
Could the extents be set automatically at the beginning and end of the object in question? Those can be fuzzy concepts, but for the apple there are certainly points in time at which we say “definitely a bud and not a fruit” and “definitely inedible decayed biomass.” So those could be its extents.
The extents for the tome are fuzzier. Its beginning might be when its blank vellum pages were bound and its cover decorated. But the future doesn’t have as clean an endpoint. Pages can be torn out. The cover and binding could be removed for a while and the pages scattered, but then mostly brought together with other pages added and rebound. When does it stop being itself? What’s its endpoint? Suddenly the Eye has to have a powerful and philosophically advanced AI just to reconcile Theseus’ paradox for any object it was pointed at, to the satisfaction of the sorcerer using it and in the context in which it was being examined. Not simple and not in evidence.
Auto-extents could also get into very weird mapping. If an object were created last week, each single degree of right-hand-pronation would reverse time by about 2 hours; but if was fated to last a millennium, each single degree of right-hand-supination would advance time by about 5 years. And for the overwhelming bulk of that display, the book wouldn’t change much at all, so the differences in the time mapping between the two would not be apparent to the user and could cause great confusion.
So setting extents automatically is not a simple answer either. But between the two, starting with the extents automatically saves him the work of finding the interesting bits. (Presuming we can solve that tricky end-point problem. Ideas?) Which takes us to the question of the best display, which I’ll cover in the next post.