2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/105157We describe a construction for d-polytopes generalising the well known stacking operation. The construction is applied to produce 2-simplicial and 2-simple 4-polytopes with g_2=0 on any number of n >= 13 vertices. In particular, this implies that the ray l_1, described by Bayer (1987), is fully contained in the convex hull of all flag vectors of 4-polytopes. Especially interesting examples on 9, 10 and 11 vertices are presented.20 pages, 18 figures; minor corrections and changes in notation, added referenceCombinatorics52B05; 52B12text