I think what they're doing with those sculptures is that they're taking three sine waves of different frequencies A, B, and C, and that the sculpture is the path that the point (cos(A t), cos(B t), cos(C t)) takes over the combined period of all three frequencies. That's why it's cube-shaped; x, y, and z each vary from -1 to 1 over the respective periods of each component. Like a 3D Lissajous figure; see this (https://gfycat.com/angelicdismalamazonparrot) for a 2D example.

But I also agree that I shouldn't have to be guessing like this, and that it'd be better if they had more explanation.