Once upon a time I was a student. We had QBasic programming with graphics involved in it. Once I was thinking about animation as we were told in the classroom. In order to perceivably move an object, we were supposed to draw the object, erase the screen, give some delay then draw the object again at a slightly different position....repeat the same thing all-over...
I suppose I had not done this exercise even once.. I might have seen it happen at our labs, I did not like it.. because I was clearly able to make out that screen is clearing...there was too much fluctuation..it did not look good as an animation..
I tried to better the process by redrawing in black color instead of calling a clearscr() routine and keeping all other things same.

I had also put an infinite outer loop so that I can see the process all over again after the circle (it was a circle I was moving btw), started from one end of screen and reached the end of screen.

As I hit F5, I was so impressed by the results...that I kept staring at it for 10 passes of the circle.. it was pretty darn smooth..