Here is what will happen...Come Sunday I will say, for example, "make something using a 1.5" square block of material". It can be anything you want, out of anything you want, as long as the exterior dimensions are 1.5x1.5x1.5. I may ask for something made out of a short length of round stock, or something rectangular, or something attached with a single bolt, or something interlocking.
The only specifics you will be asked to maintain are base measurements of the material. Everything else is up to you. It doesn't have to be a functioning item for any specific application unless that is what you want. This competition is all about being creative and I can only assume that fixturing will play a large part in this.