It is no longer a simple dump truck or cement mixer, but some vehicles with new purposes and names we have never heard before, such as towpik (note: he deliberately spelt it "pik" as it is special, so according to him it is not typo) truck, fire taxi truck and ear truck. The names are odd and sometimes hilarious and seem meaningless, but Marcus will tell us otherwise. He has little stories for each and every of his invention and they all serve different purposes. The towpik truck can tow other vehicles and also pick up rubbish and a fire taxi truck can carry people during and through a fire. Hmmm... he sure has some good imagination there. I couldn't really fathom his explanation of what an ear truck does though.
He doesn't just draw them, but also build different models of vehicles with his mega blocks and Lego and would explain at length and with conviction what he is doing and how and why everyone is so special. We call him our little innovator.