No, it's not a little altar on my desk. These are two sets of six identical wooden pyramidal blocks which can be assembled points-in to form cubes, and points out to form a regular dodecahedron (for the ones on the left) and a rhombic dodecahedron (for the ones on the right). I made these with a table saw almost 20 years ago and I'm lucky to still have all my fingers. I got the idea from an amateur scientist column, I think, and spent a long time at the chalkboard working out what all the angles would be for the regular dodecahedron blocks.
Here's the regular put together. You can see three of the pentagonal faces. There's a cube-shaped space in the middle currently being occupied by the solid wood cube in the first picture above.
Here's the rhombic first points out, and then folded in on itself.
Here's the regular folded up. There's an interestingly shaped cavity in the center when it's closed up.