[laser cut pyramids]

Hoping someone can help. I'm new to this

One of my students wants to make 300 pyramids of different sizes, each comprised of 4 triangles, that will be laser cut from acrylic. I'm looking for an easy and straightforward way to help him with as few lines as possible, and the least waste. Here are the steps and the gaps. 

1. make a triangle of the correct size, e.g., 11" x 2.5" and set it with no fill, stroke pure red and .001pt -- easy to do

2. copy and paste a new one on top of the first one -- easy to do

3. rotate this second one 180 degrees -- easy to do

4. move it so that the sloping left side of the second one is exactly on top of the sloping right side of the first. (is there something that allows them to snap, or indicates that they're aligned?)

5. eliminate the extra shared line between the two triangles and merge into a single shape comprising 2 triangles made from exactly 5 lines.

6. copy and paste this new shape of 2 triangles and align it with the other, and merge to make a single shape which will cause the laser to cut 4 triangles using 7 lines (5 sloping sides, top and bottom). It should look like attached file.

thanks.