H4E1P3T1A1H4E1D2R1O1N1
20 points
HEPTAHEDRON is validvalid
a seven-sided polyhedron [n HEPTAHEDRA, HEPTAHEDRONS]
a solid figure having several plane faces [n HEPTAHEDRA or HEPTAHEDRONS]
a seven-sided polyhedron [n HEPTAHEDRA, HEPTAHEDRONS]
a solid figure having several plane faces [n HEPTAHEDRA or HEPTAHEDRONS]