REM Start of BASIC! Program

GR.OPEN 255,0,0,0,0,1
GR.SCREEN sx,sy
w=INT(sx/4)
h=INT(sy/6)
GR.BITMAP.CREATE bmp1,w,h
GR.BITMAP.CREATE bmp2,w,h
GR.BITMAP.DRAWINTO.START bmp1
GR.COLOR 255,0,0,0,1
GR.RECT vd,0,0,w,h
GR.COLOR 255,255,0,0,1
GR.CIRCLE vd,w/2,h/2,w/2-5
GR.COLOR 255,0,255,0,0
GR.SET.STROKE 5
GR.RECT vd,w/4,h/4,w/4*3,h/4*3
GR.BITMAP.DRAWINTO.END

GR.BITMAP.DRAW gob1,bmp1,0,h
GR.BITMAP.DRAW gob1,bmp2,w,h
GR.RENDER

x2=0
x4=w
DO
 FOR j=0 TO w/2-2 STEP 2
  x1=j
  x3=w-j
  
  FOR i=0 TO h-1
   a=x1+(x2-x1)/h*i
   b=x3+(x4-x3)/h*i-a
   GR.BITMAP.CROP bmp3,bmp1,0,i,w-1,1
   GR.BITMAP.SCALE bmp4,bmp3,b,1
   GR.BITMAP.DRAWINTO.START bmp2
   GR.BITMAP.DRAW vd,bmp4,a,i
   GR.BITMAP.DRAWINTO.END
   GR.BITMAP.DELETE bmp4
   GR.BITMAP.DELETE bmp3
  NEXT i
  GR.RENDER
 NEXT j

UNTIL 0