This is a screen shot from one of several "Doily" program I wrote in QuickBASIC. This one puts a continually changing abstract pattern of spreading lines in different colors onto my monitor screen. It would probably make a nice, if slightly old-fashioned, screen saver (it's low-res, at 480 x 640 in 16 colors; the maximum available in the version of QuickBASIC I have). I enjoy running it now and then, just to watch. Others like that depicted here are Serpentine and Cosmology.