go dat
sw user sem7
de-sy a b
get
go p-3
s-a-v 1 x(b) 0 1 .01
s-c t=500
c-e
step n
po
s-d-a x x(b)
en t gmu
Gm mur(a) mur(b)

s-d-a y gmu

s-s y n -10000 5000
s-l d
pl
SCREEN
set-interactive