Still Life with Envelope

I was playing with the tying to the edge idea again. Also, I wanted to make the back part of the painting tip forward by using white in the background -- to flatten the picture plane, flatness and depth together. It's much more clean edged than I intended, what was I thinking....

The turquoise painting was the first one, and that bright strip at the bottom was one diagonal too many. In the top painting, I used a gray purple in that space and the composition has enough of a vertical now so that it works better. I wonder what I learned here.