  Greene and Owens explore cubiquitous lattices as an obstruction to rational
homology 3-spheres bounding rational homology 4-balls. The purpose of this
article is to better understand which sublattices of $\mathbb{Z}^n$ are
cubiquitous with the aim of effectively using their cubiquity obstruction. We
develop a geometric obstruction (called the Wu obstruction) to cubiquity and
use it as tool to completely classify which sublattices with orthogonal bases
are cubiquitous. We then apply this result the double branched covers of
alternating connected sums of torus links. Finally, we explore how the Wu
obstruction can be used in conjunction with contractions to obstruct the
cubiquity of infinite families of lattices.
