The shape of a rectangular prism in (d + 1)-dimensions is defined as Y
= (Y-1, Y-2, ..., Y-d), Y-n = Ln/L(n + 1) where the L(n) are the pris
m's edge lengths, in ascending order. We investigate shape distributio
ns that are invariant when the prism is cut into two, also rectangular
, prisms, with one prism retained for measurement and the other discar
ded. Interesting new distributions on [0, 1](d) arise.