I have two Stella4D versions of the vertex figure for the uniform compound of ten {3,5/2,5}. The first version failed to generate the compound (it got lost), but the second one, created yesterday, found it correctly(!), to my surprise and delight. (Note to Robert W.: I can send you the .stel files i...

The uniform compound of five quasitruncated grand stellated hecatonicosachora is chiral, but its set of vertices is not. So when the compound is combined with its mirror image into a compound of ten, their combined 14400 vertices double up, and the convex hull of the ten-compound is the same figure ...

Here are two views of the uniform chiral compound of five quasitruncated grand stellated 120-cells (hecatonicosachora). Stella4D makes these with her truncate function. The cells of a component are 120 quasitruncated stellated dodecahedra and 120 great dodecahedra; the vertex figure is a pentagramma...

I found that the "tetrahedral" compound of two great dodecahedra used as a vertex figure will generate the compound of ten grand stellated 120-cells {5/2,5,5/2} via Stella4D. So I was also able to construct the chiral compound of five grand stellated 120-cells by deleting the correct choice of five ...

Ah--I recognize Jonathan B. "by his paw."

I forgot to mention that, thanks in part to Stella4D, the pictures above are almost certainly humanity's first actual look at these monster compounds.

Here are Stella4D pictures of central 3D cross-sections of the compound of 200 icositetrachora in a 120-cell: http://members.aol.com/Dinogeorge/200icos.gif and its dual compound of 200 icos about a 600-cell: http://members.aol.com/Dinogeorge/200icosdual.gif (This is my first attempt to post pictures...

I finally built Stella4D models of the two uniform compounds of 200 icositetrachora. These are "strongly" uniform: Their vertices are transitive on the symmetry group, and so are the individual components. The harder of the two to build is the compound of 200 icositetrachora in a 120-cell, and the o...

I haven't tried these compounds since version 4.2 at earliest, so maybe the change occurred with 4.3. I can now also make the compound of 75 16-cells directly from its vertex figure (compound of five octahedra) and no longer obtain the "weirdo" compound pf 219 icositetrachora (remember that one?). I...

I continue to find more 4D compounds that Stella4D can construct. The latest is the uniform compound of 225 icositetrachora in a 120-cell, whose vertex figure is a compound of nine cubes. Extremely complicated!

I was playing with Stella4D version 4.4 and was pleased to discover that it will now construct the 4D compounds of ten 600-cells and ten grand 600-cells from their vertex figures, which are compounds of two icosahedra and two great icosahedra, respectively. Earlier versions of Stella4D became lost t...