[Someone]

Mathematically, I think they both may be tetrahedons. The Tetrapod models it by 4 lines connecting each of its vertices to its center, the Dolosse by two opposite edges connected by a line through the middle.

I’m saying “may be” because it is possible that the center “arm” of the Dolosse is too large to make a true tetrahedon. That’s a degree of freedom in the design.

> It would be interesting to know if, specifically, those geometries were chosen specifically to be placed in those two parts of the wall

My guess would be that Dolosses interlock better than Tetrapods, allowing for steeper inclines on stacks of them.

[close04]

That connecting "spine" is there to improve the interlocking of the tetrapods. They can "hook" better to each other. That's the theory at least, I don't know the if it's better in practice.