\ Copyright (c) 1987-2007 by Frank H. Rothkamm. All rights reserved.
quan random_x 300 to random_x
quan random_y 200 to random_y
quan random_step 2 to random_step
: buterfly
300 to random_x
200 to random_y
['] noop is mouse-routine \ no double program
erase-screen
begin
\ ------------------------------ butterfly ------------------------------
right-button if random_step 1+ 100 min to random_step then
left-button if random_step 1- 1 max to random_step then
random_x brnd if random_step + 629 min
else random_step - 1 max
then to random_x
random_y brnd if random_step + 389 min
else random_step - 1 max
then to random_y
brnd if grey-fill else black-fill then
random_x x1 ! random_y y1 ! 9 y2 ! 9 x2 !
box(filled)
key? if
['] graphic is mouse-routine
1 char-color !
erase-screen exit
then
again
;