Years ago, I wrote this tiny subroutine in PostScript:
/box { % draw a box given lower left and upper right corner coordinates
 2 copy moveto
 3 index exch lineto
 3 -1 roll 2 index lineto
 exch lineto
 closepath
} def
All it does is define a rectangular path given by four numbers. So to draw a box from (0,0) to (100,50), you’d say
0 0 100 50 box stroke
This code still pleases me because:
- it accepts arguments in a sensible order
- it uses no local variables, relying purely on the stack
- no spare values have to be popped from the stack at any time.