Re-inventing the wheel!
The 4 sets of square tyres were recently unearthed from under a ton of store-room crap at a UK mountainboard centre. They're apparently from 2003 when Primo Strikers were the kings of rubber, adorning all manner of boards like Scrubs to Earthboards. They tried all manner of developments; tread, thickness, density etc when (legend has it) the inspiration came from driving 'corrugated' roads in Australia. Only half the roads in Oz are tarmac and these majorly rutted red dirt tracks can shake your car apart so you have to drive at under 10mph. Or over 40mph! the wobbles & noise magically stop and suddenly you're just gliding as the round tyres only touch a small percentage of the zig-zaggy edges of the ground. These mountainboard tyres work on the same principle but vice versa.
Of course they are totally rubbish going slow. However, put them on a severe slope, gravity takes hold and so long as the rider holds steady, in a few seconds the wheels are at optimum rpm. At that point there is less rubber in contact with the ground therefore less friction therefore a smooth fast mind-blowing ride.
When trying them out (as seen in Daz's photos) the riders found them hilarious and annoying.
They could get good speed up and described it as like riding a hoverboard, but could barely turn without catching an edge. And hitting jumps was fine but and upon landing the tyres would not all pick up where they left off leading to many a bail...
You can see why they never went into production, but hats off to the crazy genius lunatic inventors, and to the riders for giving them a go!