This most often occurs with grooving tools, because the edge is rubbing along the side of the groove rather than cutting into the worked material. Again mostly associated with grooving, but type B can occur with some cutting motions. This type of distribution can be produced by a number of activities and therefore is not functionally discriminatory. The asymmetry of this distribution often indicates the leading aspect of the edge and so helps to determine the motion of the tool. This can indicate that either two separate activities are involved, or that two quite different materials are involved in the same activity as when cutting plants on a wooden board.
Some tools can have more than one type of distribution.
In order to establish the distribution type of test tool 34, the working edge can be drawn as a straight line. This combination of distribution types is highly diagnostic of the motion of the tool, as it is produced by the point being the leading aspect of the working edge, hence the asymmetric distribution. This is most often associated with the amount of penetration of the material, which can indicate whether the material was soft, medium or hard. However, the contact angle can also affect the invasiveness of the polish. The reason for differentiating between linear features and striations is that though the precise mechanism of polish formation is not fully understood, linear features and striations have different mechanical origins.