I played with this a little bit.  I like the idea, but I think it also opens up opportunity for unexpected results.  For instance if `left='abc'` and `right='cde'` then the above succeeds and returns `'<itertools.chain object at 0x5f5ed10>'`.

We'll need to come back to merging meta for more realistic use cases, but for now I'll leave the strict but predictable version in place.