Because dream it, and, provided you’re making enough Youtube money, you can achieve it, this is a video of The Q constructing and riding a bicycle with tires made out of 60 tennis balls. I bet dogs love chasing him! It looks like it rides surprisingly well (and never needs air added for the life of the balls), and I wonder why bicycle makers have never offered tennis balls wheels (tennis bwheels) in the past. Or made wheels triangular. Or just stop beating around the bush and make hoverbikes already. This was supposed to be the future!