  We elaborate on aspects of a new positive geometry proposed recently, which
was conjectured to be the four-point amplituhedron for ABJM theory. We study
generalized unitarity cuts from the geometry, and in particular we prove that
(1) the four-point integrand satisfies perturbative unitarity (or optical
theorem) to all loops, which follows directly from the geometry, and (2)
vanishing cuts involving odd-point amplitudes follow from the ``bipartite"
nature of the associated ``negative geometries", which justifies their
appearance in ABJM theory. We also take a first step in integrating the forms
of these negative geometries and obtain an infrared-finite quantity up to two
loops, from which we extract the cusp anomalous dimension at leading order.
