Fantastic Contraption

So John and I have a new hobby: We make physics devices from two to five in the morning while our kids are sleeping, for a date. I like triangles and cars, which I used exclusively until level 13, so this is just a different kind of car than I'm used to making. We couldn't embed the game, but here's a link (push continue then the start button):

My Cute Tank!

Post any cool designs in the comments!