Inspired by a Steve Ramsey video about making a wooden duck pull-toy, I knocked out a wooden duck push-toy. I had a really tough scrap of 2×8 laying around, and the jigsaw had trouble cutting a fine shape out. A lot of sanding ensued, and the wood kept absorbing the yellow latex craft paint I had on hand. I think that would have been fine but I got a can of yellow spray paint and now this duck can be seen from space.
The wheels are just large dowels, and the axle is straight enough to allow a slight wobble. As this was being built for my younger son I gave him the option of push toy or pull toy. He opted for a push toy, and I made the push stick about the right size for him.