Could you clarify what "double sided three dimensional triangle" means?
Do you mean a triangular prism, a tetrahedron, pyramid or what?
Thanks!

The triangle referred to in the project is just like two triangles joined together. The base is like a v and there are two triangles joined in the middle.

Hi
Thanks for your invitation.
I have worked for your project, you can view my designs.
I await your feedback.

Regards