RECYCLED MATERIALS this time: plastic caps, plastic bottle from liquid soap.
The last car I made had the wooden trunk, this one has a plastic one. Why actually spend time making trunks if you can easily re-purpose an old plastic bottle - the bottoms of them are just PERFECT for trunk making.
And this is how it evolved - white trunk needed white wheels, but then the whole piece just looked drab, so I stained it with walnut stain so that the white details pop up.
There's also another pic so that you can see what the wheels look like when I bake them. As long as they are hot, I dismantle them, glue and joint them back. Done.