Using his toy for a model, this is what I cut out.
I then used a rather large star tip, and simply piped the entire thing with grey frosting. It proved a little tricky in some spots, but wasn't too bad over all. My mother helped with the piping which was great because my poor old hand isn't what it use to be when it comes to all those little piped stars.
Camden told me after his party was over that this cake was his favorite cake that I'd ever made him. I love making special birthday cakes for the boys. I have so many good memories from cakes that my mother made for me growing up, so I hope my boys will, too.