keypunch.icn: Program to simulate a keypunch

   In the olden days, computer data was encoded by rectangular holes
punched in thin pieces of cardboard about the size of an old dollar.
This program simulates a "keypunch", a mechanical device for punching
those holes.  (Keypunches themselves were programmable, but there's
no way to program this one; tab stops are set permanently.)

   A carriage return feeds a new card.  Illegal characters punch a
lace column.  As with a real keypunch, you can backspace, but the
holes don't go away.

   The shift key turns "UIOJKLM<>" into "123456789".  The meta key
serves (imperfectly) as the multipunch key.

   The font was chosen on a Sun workstation and may not be portable.