This is plumb.c and pced.c taken from the plumb distro at
  http://basalt.cias.osakafu-u.ac.jp/plan9/s52.html
with some changes.

regarding plumb.c:
 - to avoid taking up 100% cpu I use timer events
   to avoid continuously calling fugit()
 - the above change also solves the problem I had
   that when a game is lost and then a new game is started
   the screen is only updated when the mouse is moved
   or clicked
 - explode now gradually overwrites with white
   (unfortunately I do not have plan 9 2ed so
        I do not know the intended effect of explode)
- now use a mask in the reservoir filling animation
- tried to clean up some warnings (from ?c -FVw).

regarding pced.c:
 - fixed color problem, it now draws the pieces

Because the game was too difficult for me,
I also commented out the line that 'awards' doublecross
only 5 at a time.

Axel.