The Oval shape is the less common shape among constructivist, but is was at one time used by some great names in art. Piet Mondriaan used it and also Roy Lichtenstein was a fan and used the shape in his Mirror paintings. Put them beside each other and you will notice similarities between the two. Not only the shape , but also how the space is filled with the composition. I noticed this because a few weeks ago i went to an auction viewing and found the drawings by Henk de Looper for auction. All oval shaped and they really fascinated me.
Here is some information on this forgotten artist who deserves better and is represented by gallery PHOEBUS in Rotterdam.