Answer is quite simple actually:Don wrote:1. The Ippo's claim to be fresh and original.
2. Vas claims to be fresh and original.
3 Houdart claims to be fresh and original.
1. Ippo is as original as Komodo, R3 is RE, ideas are taken, new program is written.
2. R1 and R2 are not, R3 almost certainly clean code wise, therefore according to your "free taking of ideas is ok" motto, is also original.
3. Houdini 1 and 1.5 in smaller matter are certainly not original, but are completely legal. There is chance the Hounding 2.0 is clean code wise, but I seriously doubt it.
Regarding 1. and 2. and Bob's rotated bitboards, table coefficients (not acquired by tuning) are certainly not something that violates copyright, therefore doesn't violate originality assumption either.