Please refer to the following codes. ACLS:GPAGE 0,0:GCOPY 4,0,0,511,511,0,0,TRUE DIM TMP%[512*4] WHILE TRUE VSYNC 1:B=BUTTON(0) W=4+508*(B==1 || B==2) H=4+508*(B==4 || B==8) GSAVE 0,508*(B==4),508*(B==1),W,H,TMP%,1 GCOPY 0,4*(B==8),4*(B==2),511,511,4*(B==4),4*(B==1),TRUE GLOAD 508*(B==8),508*(B==2),W,H,TMP%,1,TRUE WEND