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Challenges

# Prove commutativity on this monoid presentation.

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Given two binary strings $A$ and $B$ such that $A$ is an anagram of $B$, output a third binary string $S$ such that both $A$ and $B$ can be created by iterated removals of the substring $10101$ from $S$.

For example for $A=100$ and $B = 010$, one solution is $S = 10101010$ since

$$(10101)010 \rightarrow 010$$$$10(10101)0 \rightarrow 100$$

For a more complex example if $A = 1100$ and $B = 0101$, then one solution is $S = 11010101010101$ since

$$110(10101)010101 \rightarrow 1100(10101) \rightarrow 1100$$$$1(10101)01010101 \rightarrow (10101)0101 \rightarrow 0101$$

There are multiple solutions to every possible input, but there is no requirement that the output be any particular one, only that it satisfy the requirements.

This is code-golf, the goal is to minimize the size of your source code as measured in bytes.

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