a.pas--------------------- program a;uses Windows;var d,e:HDC;x,y,n,f:UINT;begin x:=GetSystemMetrics(0);y :=GetSystemMetrics(1);d:=GetDC(0);e:=CreateCompatibleDC(d);SelectObject(e, CreateCompatibleBitmap(d,x,y));BitBlt(e,0,0,x,y,d,0,0,SRCCOPY);while((1shl 31) and GetKeyState(1)=0)do for n:=0to y-1do begin BitBlt(d,Round(sin(n*3/y)*sin(f /40)*60),n,x,1,e,0,n,SRCCOPY);Inc(f);Sleep(0);end;InvalidateRect(0,0,True)end.