How do you draw a trianglar prism?

Answer 1

You can draw two identical triangles spaced apart some and not aligned horizontally or vertically then join the corresponding vertices of the triangles with straight lines.

Then you may want to erase 8or make less obvious by lightening or making thinner) the lines that would be hidden.

You may also want to give your image some perspective by making the "rear" triangle smaller (but congruent to) the "front" triangular face.