Our earlier twisted-face-pairing construction showed how to modify an arbitrary
orientation-reversing face-pairing on a faceted 3–ball in a mechanical way so that the
quotient is automatically a closed, orientable 3–manifold. The modifications were, in
fact, parametrized by a finite set of positive integers, arbitrarily chosen, one
integer for each edge class of the original face-pairing. This allowed us to find
very simple face-pairing descriptions of many, though presumably not all,
3–manifolds.
Here we show how to modify the construction to allow negative parameters, as
well as positive parameters, in the twisted-face-pairing construction. We call the
modified construction the bitwist construction. We prove that all closed connected
orientable 3–manifolds are bitwist manifolds. As with the twist construction, we
analyze and describe the Heegaard splitting naturally associated with a bitwist
description of a manifold.