Hi Maria,

> can i ask what you mean by a 'mathematical alphabet'?
The alphabet is Σ
Σ = {a,b,l,m,r,w,s,p,n}
* a = prefix marker
* b = signbox marker
* l = left lane marker
* m = middle lane marker
* r = right lane marker
* w = writing symbol
* s = sequential symbol
* p = punctuation symbol
* n = number token

Section 4 of the Modern SignWriting specification deals with the 
mathematical model.

More in depth reading is available on Wikipedia under formal language 

> does this mean that the same number of variations
> apply to all symbols - or something like that?
There is part of that.  Every base symbol has a specific number of valid 
fills and rotations.  If symbols are variations of other symbols, then 
they all have the same valid fills and rotations.

> wow - it is wonderful to hear about configuring the ISWA 2010 for easy
> sub-sets or for more complex custom sub-sets! So in theory each language
> could have his own symbol-set in Puddle?
Yes, the easy configuration is easy.  The more complex custom sub-sets 
are theory only.

> If you would ever like to use the LSM Puddle with results from this small
> section of my work about base symbols as a dummy experiment..please just
> ask, i hope to complete this section soon.
Excellent.  I'll keep you informed.