We need their facial features to look clear and the background to blur away.
Christopher, who is also the author of four novels and a study of film noir, is an enjoyably indulgent director: "You're dreaming of the velodrome / the rings of Saturn spinning / with riders who blur away / like those fast-motion films / of flowers blossoming and dying".
The lines between need and want blur away as the shopping lists are checked off, check-out lines grow longer and longer, people get angrier, and retail staff try to stay out of the fray.
Other, perhaps more convincing pieces of evidence for indeterminate appearances include our inability to say exactly how far away certain objects seem to be, our inability in some cases to say merely on the basis of appearances whether two objects are the same color, and our inability to read blurred or far-away words.
The outlines of buildings, even trees, only a hundred or so metres away are blurred and vague.
That's points off, of course, but real background blur also ramps up smoothly on either side of the focal point, meaning things near the sharp part will be only slightly blurred, while items far away like distant lights will be reduced to circular smudges.
The conch snail (blurred, left) is "leaping" away from the Marbled Cone (end showing, right), a "spear" hunter that shoots poisonous darts into its prey, if it gets close enough.
While the lines between government and business have often become blurred, this doesn't take away the necessity to maintain such lines.
As users continue to talk, the blur fades away – but users can opt to add it back if they want to remain hidden.
Some textures get blurred pretty soon if you move away from them.
