Look up OpenHexagon. It's a clone that's been up for quite some time now. Terry Cavanagh has expressed no issue with clones, and he was credited properly in it. Also, all I'm is saying that you shouldn't be misinterpreting the law, because that can lead to more problems. Remaking a copyrighted game to be a carbon copy without permission is against the law. It is something a bootlegger would do.