Mabel started by laying the blocks out in a big, mostly horizontal color-pattern..
Then she suddenly decided to make a red tower.
Last picture shows the most embellished version of the Red Tower. Mabel came up with the idea of inserting the yellow triangles at a perpendicular to the plane of the rest of the structure. She insists on symmetry and order. That she loves order is paradoxical, because she also loves chaos.