on timer
   sz -= 2
   if sz < 0
      sz = 49
      color random 1000 - 1
   .
   move 50 - sz 50 - sz
   line 50 + sz 50 - sz
   line 50 + sz 50 + sz
   line 50 - sz 50 + sz
   line 50 - sz 50 - sz
   timer 0.2
.
timer 0
