;https://observablehq.com/d/4166d1225b36a920
t.f=0
frequency.f=8
shift.f = 2 * #PI / 3
amplitude = 32/2
n=360

For i=0 To 2
  CreateImage(i,640,480)
Next i

If InitSprite() And OpenWindow(0,0,0,640,480,"circlewave II",#PB_Window_SystemMenu) And OpenWindowedScreen(WindowID(0),0,0,640,480,0,0,0) 
  Repeat 
    If GetAsyncKeyState_(#VK_ESCAPE)&32768
   Break
  EndIf

    For j=0 To 2
      StartDrawing(ImageOutput(j))
        DrawingMode(#PB_2DDrawing_Default)
        Box (0,0,640,480,0)
        For i=0 To 360
        a.f = i * 2 * #PI / n;
        c.f = Cos(a * frequency - j * shift + t);j=number
        p.f = Pow((1 + Cos(a - t)) / 2, 3);
        r=128+amplitude*c*p
        Box(320+r*Cos(a),240+r*Sin(a),6,6,255<<(j*8))
      Next i
      StopDrawing()
      Next j
      t=t+1/10

      StartDrawing(ScreenOutput())
       DrawingMode(#PB_2DDrawing_Default)
       Box (0,0,640,480,0)
      DrawingMode(#PB_2DDrawing_XOr)
      For i=0 To 2
        DrawImage(ImageID(i),0,0)
      Next i
        StopDrawing() 
        FlipBuffers() 
  Until WindowEvent()=#PB_Event_CloseWindow 
EndIf