Extended Data Fig. 6: 3D surface model images of bone tools.

Illustrated in Fig. 1. a, Bifacially-flaked tool (accession number T69L20-3009; dimensions 166 × 63 × 44 mm). The left part (cortical aspect) is fractured, almost certainly after the distal end had already been shaped (as indicated by the truncated morphology of S#1). Order of flaking can be reconstructed in part (S#5 is offset by posterior S#6 and S#4; S#3 is partially erased by S#2), and indicates a recurrent sequence of shaping of the edges near the tip. b, Tool made of a proboscidean long bone fragment (accession number T79L10-2511; dimensions 292 × 95 × 66 mm). The scars on the medullar aspect are organized in two series of contiguous removals: the left edge series are struck from the cortical side and penetrate invasively into the cancellous tissue. In the right edge, S#24-27 were removed from a pre-existing fracture plane, thus indicating that the shaping took place after the bone shaft had been split. The distal end was fractured after shaping had occurred, as part of S#22 was removed by the tip fracture, and the edge where S#21 is located was also truncated by the fracture. The V-shaped angle of such fracture runs parallel to the tool axis, which is compatible with a percussive and compressive motion likely causing the tip breakage. Each scale bar segment, 1 cm. See also Supplementary Videos 4 and 5. c, Symbology (based on¹⁰¹): 1-Direction of flaking on scar with percussion point. 2- Direction of flaking on scar where percussion point is missing. 3- Percussion point of removal on the adjacent flaking surface. 4- Position of removal with absent percussion point on the adjacent flaking surface. 5- Striking direction on undetached flakes. 6- Percussion point of undetached flake on the adjacent flaking surface.