It is based on some online layout that I cannot find. If someone recognizes it, let me know.
The corne has this shape:
┌──┬──┬──┬──┬──┬──┐ ┌──┬──┬──┬──┬──┬──┐
├──┼──┼──┼──┼──┼──┤ ├──┼──┼──┼──┼──┼──┤
├──┼──┼──┼──┼──┼──┤-------├──┼──┼──┼──┼──┼──┤
└──┴──┴──┴──┼──┼──┼──┐ ┌──┼──┼──┼──┴──┴──┴──┘
└──┴──┴──┘ └──┴──┴──┘
The corne supports four distinct layers, where each layer has different keys for each physical button. The idea is to fit a lot of keys but in a small space by these layout-switching keys.
The three keys "sticking out" from the bottom are referred as "thumb keys", since you press them with your thumb.