GWL_STYLE = -16
      HWND_TOPMOST = -1
      WS_VISIBLE = &10000000
      WS_CLIPCHILDREN = &2000000
      WS_CLIPSIBLINGS = &4000000

      SYS "GetSystemMetrics", 0 TO xscreen%
      SYS "GetSystemMetrics", 1 TO yscreen%
      SYS "SetWindowLong", @hwnd%, GWL_STYLE, WS_VISIBLE + \
      \                    WS_CLIPCHILDREN + WS_CLIPSIBLINGS
      SYS "SetWindowPos", @hwnd%, HWND_TOPMOST, 0, 0, xscreen%, yscreen%, 0
      VDU 26

      FOR X% = 0 TO xscreen%*4-4 STEP 4
        RECTANGLE FILL X%,yscreen%*3/2,2,yscreen%/2
      NEXT
      FOR X% = 0 TO xscreen%*4-8 STEP 8
        RECTANGLE FILL X%,yscreen%*2/2,4,yscreen%/2
      NEXT
      FOR X% = 0 TO xscreen%*4-12 STEP 12
        RECTANGLE FILL X%,yscreen%*1/2,6,yscreen%/2
      NEXT
      FOR X% = 0 TO xscreen%*4-16 STEP 16
        RECTANGLE FILL X%,yscreen%*0/2,8,yscreen%/2
      NEXT