The dimensional coordinates are 4d by (n-4)d, the tetrahedra lie by
pairs in each of the 16-chora given as points in the second (n-4) figure.
N = (2,0,0,0) normal, or canonical 4-cross
E = (1,1,1,1) half-tesseract with even nr of (-) signs
O = (1,1,1,-1) half-tesseract with odd nr of (-) signs
x = (0,0,0,0) a point
X = (2,2,0,0) a 24-choron.
6D. The opposite space to 4d is 2d,
2_21. Triangle vertex x with edge centres N, E, O
1_22 Hexagon, vertices N,E,O,N,E,O, centre X
7D. The opposite space here is 3d.
3_21. Cube vertices x, face centres marked N,E,O so same letter on
opposite faces. 6*8 + 8 = 56
2_31 Octahedron x, centre point X gives 30 points
Edge centres of octahedron marked N,E,O, such that a diametric
square is marked in the same letter. 12*8+30 = 126
8D The opposite space here is 4d.
4_21 Xx, xX two orthogonal 24-cells makes 48
EE, OO, NN three bi-16choron prisms makes 192