I remember when I was learning programming for the first time in my life (self-learning, with the Italian reference manual of a 2nd hand TI99/4a home computer): they stressed out the importance to avoid using visually-ambiguous identifiers, because some characters could be mistaken (i.e. '1' with 'l', 'o' with 'O' and with '0').
-- Lorenzo
My bank once send me a password, that look like a number.
After many unsucessfully logins (then block any more attempts),
I had to call them to fix it.
Even they cannot login !
Finally I suggest just cut + paste it to the password field, and it work !
Reason ? the "number" is mixed *only* with I O !!!
Now, I write number 0 with a slash in it, 1 with exaggerated slant.
And, I never use O, I as variable name (lowercase ok)
