Toggle Rule

[atom]

T is the function, means "toggle-case". This function requires exactly one single parameter.

T0: 0 is the parameter = change case of position 0
T1: 1 is the parameter = change case of position 1
T9: 9 is the parameter = change case of position 9
T10: 1 is the parameter = change case of position 1

Thats why you have to encode everything > position 9.

A = position 10
B = position 11
C = position 12

and so on..

TA: A is the parameter = change case of position 10
TB: B is the parameter = change case of position 11