I ❤ Ruby
ruby\ndef ambiguous_coordinates s\n    f = -> s do\n        r, z = [s], s.size\n        return r if z == 1\n        return (s[/^0/] ? [] : r) if s[/0$/]\n      
```ruby\ndef ambiguous_coordinates s\n    f = -> s do\n        r, z = [s], s.size\n        return r if z == 1\n        return (s[/^0/] ? [] : r) if s[/0$/]\n        return [\'0.\' + s[1..]] if s[/^0/]\n        (1...z).reduce(r) { _1 << s.clone.insert(_2, ?.) }\n    end\n    (1...(s = s[1..-2]).size).flat_map do | i |\n        f.(s[...i]).product(f.(s[i..])).map do\n            "(#{_1.first}, #{_1.last})"\n        end\n    end\nend\n```
['Ruby']