I don't have any idea what algorithm it uses, but it seems
to rely on the direction in which the stroke occurs. I've
never been able to get it to consistently recognize symbols
and I've been thinking that this could be why.
For example, if you draw a lowercase alpha starting from the
top Maple consistently recognizes it, start from the bottom
and it will never recognize it. Same thing for capital sigma.
Lowercase sigma must be started from the more medial endpoint.
For many characters I think that there is a clear direction,
but for equally many, if there is a clear direction I don't
know it. For example, how do you draw a lowercase gamma?
Which do you draw first, the short line or the long line?
Do you start from the upper endpoints or the lower ones?
I couldn't figure this one out, no matter how I draw it
Maple won't recognize it.
I don't know the algorithm which it used, but I suspect
that Maple's recognition would work much better if it
was made insensitive to the direction and order in which
each stroke occurs. Unfortunately, as is, I've found
that it's too unreliable for it to be too useful.