The rig for this piece mainly relied on a combination of Points to Nulls and 3D layers in Z-space. The first rig used six rectangle shapes with each point being attached to its own null. Then rotating and moving the rectangles in Z-space to create the cube. The nulls that overlapped where parented together and parented to a main control null. Using linear expressions, I was able to add extra controls on the main null seen below that allowed me to stretch/extrude the front and back of the cube. The second rig again relied on parented points to nulls, but did not require any 3D layers.