Are Triballs Rouleaux Tetrahedrons?

When over under was initially released I was curious if the Triballs were shapes of constant width or diameter. The game manual doesn’t answer the question either, so I was wondering if anyone had some answer to my question as I don’t have the game object yet.

looks like it


I can just imagine the emcees say “Rouleaux Tetrahedron” every time a team’s robot has them in possession. Yikes!


Well I suppose that answers the question, but I still wonder if they are of constant width as I believe Rouleaux Tetrahedrons don’t necessarily have constant width.

Yes, they seem to have constant width, meaning something must be compressed to score them. Also, as Sidoti pointed out… it’s a tetrahedrally symmetrical spheroform :slight_smile:


The vex robotics logo makes it imperfect. Obviously. But more seriously, it will be very close to it. Even if it is a Reuleaux tetrahedron, it is very close to a body of constant width.

I don’t understand why they couldn’t have used ordinary spheres, it would have been so much simpler.

They’ve already done spheres a few times. I guess they just wanted to change it up and make it harder.

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Why is “simpler” important? The real world does not contain “spherical cows” much to physicists’ dismay.