FYI: I've just committed some code to tetris(6) to display the next shape
   that will appear in the game, as some sort of preview-function. If someone
   wants the old behaviour, compile with NO_PREVIEW defined.

great!


but, um, please make this *not* the default behaviour, and add a command
line switch to enable/disable it!  do not depend on the environment.  i
wouild remove this 'NO_PREVIEW' variable entirely.