A closed connected hyperbolic
-manifold bounds geometrically if it is isometric to the geodesic boundary of a compact hyperbolic
-manifold. A. Reid and D. Long have shown by arithmetic methods the existence of infinitely many manifolds that bound geometrically in every dimension. We construct here infinitely many explicit examples in dimension
using right-angled dodecahedra and 120-cells and a simple colouring technique introduced by M. Davis and T. Januszkiewicz. Namely, for every
, we build an orientable compact closed 3-manifold tessellated by
right-angled dodecahedra that bounds a 4-manifold tessellated by
right-angled 120-cells. A notable feature of this family is that the ratio between the volumes of the 4-manifolds and their boundary components is constant and, in particular, bounded.