A function that is very related to the plot of the episode is the ability to block someone. To do this, the user looks at them, sees a face-detection square appear (confirming the person to be blocked), selects BLOCK from the Zed-Eyes menu, and clicks.
In one scene Matt and his wife Claire get into a spat. When Claire has enough, she decides to block Matt. Now Matt gets blurred and muted for Claire, but also the other way around: Claire is blurred and muted for Matt.
The blur is of the live image of the person within their own silhouette. (The silhouettes sometimes display a lovely warm-to-the-left and cool-to-the-right fringe effects, like subpixel antialiasing or chromatic aberration from optical lenses, I note, but it appears inconsistently.) The colors in the blur are completely desaturated to tones of gray. The human behind it is barely recognizable. His or her voice is also muffled, so only the vaguest sense of the volume and emotional tone of what they are saying is audible. Joe explains in the episode that once blocked, the blocked person can’t message or call the blocker, but the blocker can message the blocked person, and undo the block.