Helmut Alt Sergio Cabello Otfried Cheong Ji-won Park Nadja Seiferth Packing d-dimensional balls into a d + 1-dimensional container. 102219 2026 132 Comput. Geom. https://doi.org/10.1016/j.comgeo.2025.102219 db/journals/comgeo/comgeo132.html#AltCCPS26 streams/journals/comgeo