I do not get it... R(3,3) is 6 so R(3,4) should also be 6 for you are looking for a triangle OR an interconnecting square.
And because this symetry-thinghy it should apply also to R(4,3) here it is the use of OR.
Another thing is "eight points aren't enough" if you look at the setup then every even number would behave the same so with some level of confidence you could also say "32 points aren,t enough" which is obviously not the case.