Hello, I had also issues with the sandbox code and g++. That's why I made three changes: 1) clipper.h: "const Path<t> &Path() const { return path_; };" g++ did not like that a method has the same name as a class (Path) - I changed the methods name to "const Path<t> &GetPath() const { return path_; };"</t></t> 2) clipper_core.cpp: Some methods were lacking "template<>". 3) clipper_core.cpp: The specialization of a template (PathI, PathD, PointI, PointD, etc.) function needs to be declared first before...