const PI = atn(1)*4

dim shared as short Min = 12

const ScrWid=1280,ScrHei=1024
const ScX=ScrWid/320,ScY=ScrHei/256

screenres ScrWid,ScrHei 'mode 1
window (0,0)-(1280,1024)
color 14

sub PROCC(L as short,ANGLE as single)
  if L<MIN then
    line -step(ScX+L*COS(ANGLE),ScY),,bf
    line -step(-ScX,L*SIN(ANGLE)-ScY),,bf
    sleep 1,1
    exit sub
  end if
  L = int(L/SQR(2))
  PROCC(L,ANGLE+PI/4)
  PROCC(L,ANGLE-PI/4)
end sub

pset(300,200)
PROCC(700,0)
sleep