+-------------------------------------------------+
       |           GEOMETRIC PYRAMID POD                 |
       |                                                 |
       |                       /\                        |
       |                      /  \  [ PYRAMID PEAK ]     |
       |                     /    \                      |
       |                    /  /\  \                     |
       |                   /  /  \  \                    |
       |                  /  /----\  \                   |
       |                 +------------+                  |
       |                 [ INTERLOCKING BOTTOM TABS ]    |
       |                                                 |
       +-------------------------------------------------+

How to Build

  1. Trace four equal-sized isosceles triangles onto heavy cardboard with slot tabs along the base edges.
  2. Cut a door hole into one triangle face.
  3. Interlock the slotted tabs at the peak and base to erect the pyramid; disassemble and flatten in seconds.

8. Stackable Multi-Level Cat Condo Tower

Two or three stacked cube boxes connected by interior ceiling trapdoors, giving outdoor cats multiple warm elevated sleeping platforms.