2 EricTrickster: I understand there is no way to protect idea, concept. And I don't really want it and need it. It's like FPS. iD came out with Hovertank, got to Quake and then Valve came up with HL. The same idea (FPS), but different approach. it's always a challenge - to come up with idea and bring it to unreachable altitude. Or use old concept, adopt an idea and transform it to new, better incarnation.
2 others: Thank you very much!