The elongated pentagonal gyrobirotunda is a convex equilateral gyrobirotunda having regular pentagonal upper and lower birotundas arranged rotated 1/10 of a turn
with respect to one another and separated by a strip of vertical squares. It is Johnson solid .

The unit elongated pentagonal gyrobirotunda has volume

where the first expression uses the basis of Conway et al. (1999). It can be dissected into the elongated
pentagonal orthobirotunda, with which it differs only by relative rotate of the
top and bottom rotundas.

Conway, J. H.; Radin, C.; and Sadun, L. "On Angles Whose Squared Trigonometric Functions Are Rational." Discr. Computat. Geom.22,
321-332, 1999.Johnson, N. W. "Convex Polyhedra with Regular
Faces." Canad. J. Math.18, 169-200, 1966.