SUB

S
-->
A
B B A B B A

A
B
-->
a B

B
A
-->
B
b

A
A
-->
c
c

A
B A
-->
A
d A

B
B A
-->
B
e A

The
string "ABBABBA" is rewritten "afeafeb" as shown Fig.14.

Substitutions
may be used for designing a general category of unidimensional cellular automata
and some multidimensional ones.

If
substitutions are performed on strings of terminal symbols, each step may
produce an interesting sound-object sequence. For this reason, it is possible
to instruct BP2 to play all substitutions
in the "Improvize" mode. The option is given in the "Settings" dialog. See an
application in "-gr.koto3".