Notes:

1. Short, straight, horizontal edge.
2. Inner curved edge.
3. Curved top edge.
4. Concavity.
5. Flow area.
6. Curved lower edge.

A 1 needs a narrow width, horiztonal top. There is no support for this as symbol #16 has a wide, curved top. A 1 needs long vertical edges. There is no support for this in symbol #16. This excludes a 1.

A 5 needs a wide horizontal top, a top left corner, and a short left-hand vertical edge from the top. This is no support for any of these features. This excludes a 5.

A 7 needs a wide horizontal top, and a diagonal from the lower left to the upper right. There is support for neither. This excludes a 7.

A 4 needs a left-hand vertical edge, or a diagonal from the middle-left to the upper right, and a vertical right edge. There is no support for any of these features. This excludes a 4.

A 0 requires a curved top and bottom, which symbol #16 has, but requires either convex or straight left and right edges, neither of which are present in symbol #16. This excludes a 0.

A 9 requires a closed loop on the top and a diagonal line from the lower left to the upper right. There is support for neither. This excludes a 9.

A 6 requires a short-edge inthe top right, whereas symbol #16 has a conflicting short edge in the top left. This excludes a 6.

An 8 requires a closed loop on both the top and the bottom. Symbol #16 does not appear to have a closed loop on top. This probably excludes an 8.

A 2 requires a short edge to the top left which is present in symbol #16. A 2 also requires top curvature which is present in symbol #16. A 2 also requires a diagonal from the lower-left to the upper right. There is contradictory evidence, but not necessarily exclusive, as the extent and location of lower flow is unclear in symbol #16. A 2 also requires a wide flat bottom. There is contradictory evidence, but not necessarily exclusive, as the extent and location of lower flow is unclear in symbol #16. A 2 is a possible candidate for symbol #16.

A 3 requires a short edge to the top left which is present in symbol #16. A 3 also requires a concavity on the right-hand edge which is present in symbol # 16. A 3 also requires lower curvature, which appears to be present in symbol #16.

Outline: The yellow overlay is the visible portion of the symbol’s outline. This overlay is the partial outline for a “3” which is supported by the evidence.

Conclusion: The symbol features suggest TIGHAR artifact 2-6-S-45 symbol #16 is probably a three (“3”). The most likely first alternate is a two “2.” The most likely second alternate is an eight “8.”