some distance from the base. It is possible to discern retouching or rebuilding in deteriorated parts of the edges. The following types of cross section are commonly seen: triangular (sub-triangular and backed triangular), rhombic (rhomboidal and backed rhomboidal), trapezium (trapezoid and backed trapezoidal), pentagon (pentagonal and backed pentagonal), polygonal, biconvex or lenticular (sub lenticular). Profile—By definition, hand axes have a roughly balanced outline, with a morphological axis that also serves as an axis of bilateral symmetry and a plane that serves as an axis of bifacial symmetry. Not all hand axes are perfectly symmetrical. Symmetry was achieved only after millennia of development. Symmetry may not make tools more useful. Hand axes were used in a variety of heavy physical tasks. They deteriorated, wore out and broke and were often repaired with retouching of their edges, recovery of their points or complete reworking. The majority of discovered pieces are remains, pieces that have been discarded after a long life as tools, during which they often were damaged and/or adapted for specialized tasks. Such pieces may have lost whatever symmetry they initially had. Hand axe profiles can be classified into the following categories: {| width="30%" border=1 cellspacing=0 cellpadding=2 align=center |------- | | | | | |------- | | | | | |------- | | | | | |------- | | | | | |------- | | | | | |------- | | | | | |} Dimensions and ratios Hand axe measurements use the morphological axis as a reference and for orientation. In addition to length, width, depth, specialists have proposed a wide range of other physical quantities. The most common were proposed by Bordes and Balout: Maximum length (L) Maximum width (m) Maximum depth (e) Distance from the base to the zone with the maximum width (a) Width 3/4 of the way along the piece (o) A and o can be used to delineate the contour's cross section and to measure the angles of the edges (provided this is not an area covered in the stone's original cortex). These angular measurements for the edges are made using a goniometer. Edge length, weight and the length of the chord described by the edges (if the piece has a transverse terminal bezel) can be measured. These measurements allow morphological and technical ratios to be established (for example, the relationship between the weight and the length of the cutting edges, or the relationship between