It's worth adding that the Garden analogy falls down for multiple other reasons, all of which mean that "a rope" won't do either.
The simple fact is that, as a result of Brexit, the island of Ireland has to simultaneously be separated (owing to differing customs rules on either side, assuming that the UK leaves the Customs Union) and together (owing to the Good Friday Agreement, and for that matter how the two parts of Ireland have operated for the last 90 years). Obviously, this is impossible. Equally obviously, this is a problem that *we* created, by deciding to leave before it was worked out how this was to be achieved.
By this I am not meaning to blame those who voted for Brexit, but rather those people (specifically, David Cameron) who brought about the referendum for cynical reasons -- and then ran away once they realised that this hadn't shut the Eurosceptics up.