Surely you recognize the ubiquitous Trofast storage container here - and it's been ingeniously overturned and made into an inexpensive riding toy. Googly eyes optional.
"Ten is a collective of 10 designers who share a similar approach to design and who for the last four years have been presenting different projects around the theme of environmental sustainability in design." Now in a project called Ten-Plan each member has released a project along with the instructions for how to execute it.
Sam Johnson, a parent, dreamed this project up. Besides a Trofast, what else do you need? A cutting board and casters. You can download the instructions (cheekily done Ikea-style) at Ten-Plan.