Prismantiprismoid

A prismantiprismoid is an isogonal polytope with a structure composed of alternating prisms and antiprisms and are generally nonuniform. The simplest non-trivial prismantiprismoid is the digonal-square prismantiprismoid. The dual of a prismantiprismoid is a tegmotrapezohedroid. All prismantiprismoids are edge-snub polytopes. They are also a special class of the duoprismatic prismantiprismatoswirlprisms, having only two polygonal rotations for each ring.

Unlike other duoprismatic families, the n-m prismantiprismoid is not equivalent to the m-n prismantiprismoid, meaning that the square-hexagonal prismantiprismoid and the hexagonal-square prismantiprismoid are not topologically the same polychoron, as the former has 6 rings of alternating square prisms and square antiprisms, while the latter has 4 rings of alternating hexagonal prisms and hexagonal antiprisms. Another additional restriction is that n must be an alternated polytope (such as a snub cube), while m must be an alternable polytope (such as a hexagonal prism).

Special cases
In four dimensions, an n-m prismantiprismoid can have the least possible edge length difference, assuming that the edge lengths belonging to the n-gon and the longest edge are 1, if the n-gonal prism height is equal to (sec(π/2n)cos(π/m)$\sqrt{3+2cos(π/n)+2cos(2π/m)}$-1)/(2+4cos(2π/m)). This ensures that the isosceles trapezoids have three equal edges.