This cake was for a baby shower. It's basically a 3-layer rectangular cake with a basket weave pattern around the sides... with a hood and some wheels.
A week earlier, I started on the hood. A globe worked for the form. I wrapped it in plastic wrap to make sure no food stuff touched the globe. Then I took some gum paste and rolled it out around a quandrant of the globe to get a quarter sphere. After a few days, it was dry enough to be removed from the globe. The plastic wrap helped ensure nothing stuck to the globe. It came off relatively easily.
For the outside buttercream, I used an Italian Meringue buttercream. This is made by mixing up a straight meringue and then pouring in boiling sugar, which cooks the meringue. Then, after it cools, you add a lot of butter a little bit at a time. It has a smoother texture and is great for getting a smooth frosting. It also tastes much less sweet. I gave it a pink blanket with a little fold in it and a single pink stripe around the basket weave. This was to be for a girl baby, of course.
For the base, I cut up a thin piece of cheap plywood to size and covered it with cake foil. I used a miter saw to cut four 3/4" dowels to exactly 7" each. It's all attached with screws through pre-drilled holes. For the wheels, I just made some sugar cookies. I used an apple corer as my template. It was about four inches in diameter and already had "spokes" and a "hub" for me. I just decorated with some royal icing and a dollop of pink in the middle to complete the effect. The wheels rest on the base and stick to the posts with a touch of royal icing.