painting over it

Have you ever painted over a painting?  Chatting online with a fellow artist friend of mine got me thinking about restoration (or renovation) versus innovation. Sometimes we see something old (a building, a garden, a screenplay etc) and begin tweaking with it again. Something gets edited out, added on or refinished. But for me as a painter, sometimes I'll just shake the etch-a-sketch and start over. Maybe I'll save some remnant like the colour scheme, but only in my head. Here's an example.  Circles 3 initially started out like the first image here, and now it looks like the second. Circles 10 looked like the third image, and now it looks like the fourth.  What do you think?  Have you ever "painted over" something?