Early Acheulian & Developed OldowanB / e)peninj16
Biface/Handaxe. Peninj, West Natron, Tanzania (c. 1.3-1.5 MYA). This is a typical early biface ('handaxe'). I take this to be a 'one-tiered', 4-faceted set of thematic shapes, in this case a mirror pair of convex shapes on either side and an opposition between the pointy shape(s) at the top and a rounded shape at the bottom. In other words, it may be viewed as an elongated awl. The cross-section is a reminder that in the Early Acheulian knapper is still working in only 2-dimensional symmetry.
Illustration © T. Wynn. T. Wynn. (1989). The Evolution of Spatial Competence. Urbana, IL: University of Illinois Press: fig. 16. (yellow highlight added)