Create a loop for 3 different variables to output all possible combinations - bash

Question

So lets say i have 3 lines of code
ABC
123
!##
How do i create a for loop to output the number of ways to piece them together?
E.G ABC123!##, ABC!##123, 123ABC!##$
here is my current line of code
#!/bin/bash
alphabet='ABC' numbers='123' special='!##'
for name in $alphabet$numbers$special
do
echo $name
done
echo done

Answer 1

alphabet='ABC' numbers='123' special='!##'
for name1 in $alphabet $numbers $special
#on 1st iteration, name1's value will be ABC, 2nd 123 ...
do
for name2 in $alphabet $numbers $special
do
for name3 in $alphabet $numbers $special
do
#here we ensure that we want strings only as combination of that three strings
if [ $name1 != $name2 -a $name2 != $name3 ]
then
echo $name1$name2$name3
fi
done
done
done
if you want also to print strings, like 123123123 and ABCABCABC, remove if condition

Answer 2

You can also do it without a loop at all using brace expansion (but you lose the ability to exclude, e.g. ABCABCABC). For example:
#!/bin/bash
alpha='ABC'
num='123'
spec='!##'
printf "%s\n" {$alpha,$num,$spec}{$alpha,$num,$spec}{$alpha,$num,$spec}
Example Use/Output
$ bash permute_brace_exp.sh
ABCABCABC
ABCABC123
ABCABC!##
ABC123ABC
ABC123123
ABC123!##
ABC!##ABC
ABC!##123
ABC!##!##
123ABCABC
123ABC123
123ABC!##
123123ABC
123123123
123123!##
123!##ABC
123!##123
123!##!##
!##ABCABC
!##ABC123
!##ABC!##
!##123ABC
!##123123
!##123!##
!##!##ABC
!##!##123
!##!##!##