I began with a 3D rectangle and started by sketching a hexagon in the center and then adding lines on either side to divide the outside sections. Then, I divided the hexagon into three sections and outlined all of the polygons so they could be cut out.
After outlining the shapes, I cut them out of the rectangle using the press/pull tool. I also modified the sides of the shapes to make them more irregular. The walls in the front are also lower for easier access for small things like paper clips.
Then, I chamfered the edges to make the design flow better and preserve the geometric look.