KoreanSidewalk.ps, by Tim Poston, won an honorable mention.

Tim Poston writes:

Un-Documentation
 This draws the tile pattern you see in many Korean towns.
 Counting the %! and showpage lines it's 230 characters,
 without them (but including blanks) just 218.
 PostScript 1 only.
 
 Some older displays and printers fail with it,
 because the '1 and' barfs on the large numbers rand puts on the stack;
 for such devices I add  '100000 idiv'  after  'rand'.
 But that's a kludge required by bad implementations,
 not really part of the code.
 
 Probably not obscure enough, but I'm fond of it.

How is the pattern chosen so that all the lines meet up?

What does "rand 1 and" mean?

What happens if you delete "1 setlinecap"? Is there a minimal fix for that?