ON ERROR IF ERR=17 CHAIN @lib$+"../examples/tools/touchide" ELSE MODE 3 : PRINT REPORT$ : END
      
      REM An optical illusion
      
      MODE 8 : OFF
      COLOR 1,144,208,255
      COLOR 2, 64, 64,255
      COLOR 3,255,255,255
      
      GCOL 1
      FOR X% = 46 TO 1126 STEP 216
        RECTANGLE FILL X%,0,106,1022
      NEXT
      
      GCOL 2
      FOR Y% = 134 TO 782 STEP 216
        RECTANGLE FILL 0,Y%,1278,106
      NEXT
      
      GCOL 0
      FOR X% = 46 TO 1234 STEP 108
        FOR Y% = 134 TO 890 STEP 108
          MOVE X%-20,Y%:MOVE BY 20,20:PLOT 113,20,-20
        NEXT
      NEXT X%
      
      GCOL 3
      FOR R% = 0 TO 7 : Y% = 134 + 108 * R%
        FOR C% = 0 TO 11 : X% = 46 + 108 * C%
          IF (C% EOR R% EOR R% DIV 2) AND 1 THEN
            MOVE X%-20,Y%:MOVE BY 10,10:PLOT 113,10,-10
            MOVE BY 10,10:PLOT 113,10,-10
          ELSE
            MOVE X%,Y%-20:MOVE BY 10,10:PLOT 113,-10,10
            MOVE BY 10,10:PLOT 113,-10,10
          ENDIF
        NEXT
      NEXT R%
      
      REPEAT WAIT 2 : UNTIL FALSE