half the vertices (16), bounded by alternating 5-cell and 16-cell hypercells. A 5 BC 5 D 5 5-simplex 5-cube 5-orthoplex 5-demicube The 5-simplex is self- dual , and the 5-cube and 5-orthoplex are dual to each other. The 5-demicube can be constructed by removing alternate vertices of the 5-cube. The following