I couldn't wait for UPS delivery so I used Rapidform's XOR to make a parametric model and then 3D printed up a set.
I designed these as four sided pyramids with a .75" through hole so I could insert 3/4" PVC or Black pipe, can't do this with three sided pyramids unless you use equal length pipes - not really adjustable.
Added three sided pyramid for comparison.
not much to say - just print it ...
"The usual way of finishing the top side immediately after bottom the is to flip the project and set it on a large board studded with nails. Painterâ€™s Pyramids work the same way, but unlike nail boards, they can be moved around quickly for any size project, they wonâ€™t leave prick marks in the surface, and they nest into a neat, compact stack for storage."