Vehicle (noun)
1. a means of carrying or transporting something
...such as
... a: motor vehicle
... b: a piece of mechanized equipment
2 : an agent of transmission : carrier
3: a medium through which something is expressed, achieved, or displayed
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You're thinking of specifically a __motorized__ vehicle. Which is a different thing than "vehicle". I think you'll agree that a bicycle and skateboard carry people and transport them. This is the same reason a wagon violates the rule. Almost everything on there was a vehicle. I think the only ambiguous ones are paper airplane, matchbox car, toy boat, and kite and I said those weren't because they can't transport things and are not motorized. But hey, technically they can be a medium through which someone expresses their joy.
No painting or dancing in the park.