The painting above (tricky photographing these, the black really wants to shine no matter what) consists of two paintings, one 6" square, the other 6x8". My student and I both did this exercise, doing each painting on different days and without making a great effort to match elements of the compositions. Mine can match up either way.
This is my student's painting. She has had no drawing experience but just plunged in. Her work has a modern, classic feel and she makes unusual color choices that always surprise me. This painting is more successful in the composition, it has that "fresh but inevitable" quality.