Truss - Square base - Stackable

I've built this truss parts to be stackable like lego pieces just for fun, as an example to show to my kids how to make very rigid structures while being at the same time very light.

If you want to build a large stack, build it by alternating the two main parts.
The smaller part is just to close the truss.

What is a Truss?
A truss is an assembly of beams or other elements that creates a rigid structure. In engineering, a truss is a structure that "consists of two-force members only, where the members are organized so that the assemblage as a whole behaves as a single object". A "two-force member" is a structural component where force is applied to only two points.
In this typical context, external forces and reactions to those forces are considered to act only at the nodes and result in forces in the members that are either tensile or compressive. For straight members, moments (torques) are explicitly excluded because, and only because, all the joints in a truss are treated as