Here are some quick feature notes. This is not the full list of features, more just a list of items that may not be directly obvious from
UI.
Mouse Dragging
Dragging the mouse with the left
button down will rotate the puzzle in 3D.
Dragging the mouse with the right
button down will zoom in and out.
Rotating the 120Cell
Click on any the buttons in the
lower right hand corner to start a rotation. Clicking on the left or right side of buttons affects the
rotation direction. The rotation will be in the plane of the two labeled
axes (from the directly clicked axis towards the second axis).
Click the same rotation twice to
stop rotating the 120cell.
Symmetries
There are 4 options on the
symmetries tab. The meaning of the checkboxes and colors vary depending on
which option you pick. The 120cell has so much symmetry it can be thought
of as organized in many different ways. I recommend this
paper for a more in depth explanation than I give below (Note: you don't
have to read the Mathematica code portions to get good information from
it. I particularly recommend the section "Other Properties of the 120cell" on page 15).
(1) Rings:
This option considers the 120cell
to be composed of 12 separate rings of 10 cells each.
(2) Layers:
This option considers the 120cell
to be composed of 9 layers.
Layer 
Number of Cells 
1 
1 
2 
12 
3 
20 
4 
12 
5 
30 
6 
12 
7 
20 
8 
12 
9 
1 
Layers 1 and 9 represent 2 "antipodal" cells.
Layers 6,7, and 8 are just like 2,3, and 4 in reverse, and the 5th layer is in
the middle, on an equatorial 2sphere.
(3) Tori
This option considers the 120cell
to be composed of 2 solid tori of 60 cells each. Note the first 6 rings of
the first option make up the first torus and the second 6 rings make up the
second torus (so in a way, this option is simply a convenient way to color 6
rings at a time).
(4) 4cube cells
This option considers the 120cell
to be composed of 8 groups of 13 cells and 1 group of 16 cells. Each of
the first 8 groups is centered in the 8 cells of a hypercube. The
remaining 16 fill in the gaps and are located at the vertices of the hypercube.
Checkbox 9 represents the single
group of 16 cells. Checkbox 10 will show an outline of the hypercube
defining these groups.
