It is based on some online layout that I cannot find. If someone recognizes it, let me know.
The corne has this shape:
┌──┬──┬──┬──┬──┬──┐ ┌──┬──┬──┬──┬──┬──┐
├──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┤
├──┼──┼──┼──┼──┼──┤-------├──┼──┼──┼──┼──┼──┤
└──┴──┴──┴──┼──┼──┼──┐ ┌──┼──┼──┼──┴──┴──┴──┘
└──┴──┴──┘ └──┴──┴──┘