pentagonally

In pentagonally shaped plates there is often a distal tongue or lobe slightly lower than the rest of the plate.

Walcottidiscus is a genus of pentagonally shaped echinoderms known from the Middle Cambrian Burgess Shale.

They are about 3' high, covered over with complex but now eroded swirls, spaced 50' apart, arranged pentagonally, & cut - in some unknown manner supplying us with a great deal of argumentative fuel - from the underlying granite.

The house itself features an unusual floor plan with vaguely elliptical ends: the west-facing front is linear, the east-facing rear encompasses an ell, and both the northern and southern ends are pentagonally shaped instead of flat.