Notes:
- Concavity.
- Flat lower edge.
- Curved top edge.
- Region of higher elevation. This region appears to be separate from
the symbol, possibly the result of deposition. The bottom section of
this region extends below the expected bottom edge for the symbol based
upon the adjacent symbol.
A 1 needs a narrow width, horizontal top. There is no support for this
as symbol #17 has a wide curved top. A 1 needs long vertical edges. There
is no support for this in symbol #17. This excludes a 1.
A 3 requires a short edge to the top left, a concavity on the right-hand
edge, and lower curvature, none of which appear to be present in symbol
#17. This excludes a 3.
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 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 0 requires a curved top which symbol #17 has, and also requires a curved
bottom, which symbol #17 does not have. A 0 also requires either convex
or straight left and right edges, neither of which are present in symbol
#17. This excludes a 0.
A 9 requires a closed loop on the top. While symbol #17 has top curvature,
which is a portion of what is required for a closed top loop, this level
of detail is not visible in symbol #17. A 9 also requires a diagonal line
from the lower-left to the upper right, and a narrow, horizontal foot.
There is no support for this in symbol #17. This excludes a 9.
A 6 requires a left-hand straight vertical edge, or convex edge. Symbol
#17 has a conflicting concavity on the left edge. A 6 requires a lower
loop which lower curvature, whereas symbol #17 has a lower straight edge.
There is no support for these features in symbol #17. This excludes a 6.
An 8 requires a closed loop on both the top and the bottom. Symbol #17
does not appear to have a closed loop on the bottom. This excludes an 8.
A 2 requires a short edge to the top left which may be present in symbol
#17. A 2 also requires top curvature which is present in symbol #17. A
2 also requires a diagonal from the lower-left to the upper right, however
this level of detail is not visible in symbol #17. A 2 also requires a
wide flat bottom, which appears to be present. A 2 is a possible candidate
for symbol #17.