What is the general principal for adapting 3x3 algorithms to the 4x4 and higher cubes? Algs involving just the outer layers work without change, but algs with double-layer turns don't work. An example is from the excellent "2 Look OLL" reference page on Badmephisto's website. To fix "Chameleon" on a 3x3 we can do (r U R' U') (r' F R F') but this doesn't work on a 4x4 due to the double-layer 'r' (sometimes written Rr). Is there a simple adjustment to the double-layer turns or do we just stick to the outer layers? I know that fixing "Chameleon" on a 4x4 using only the outer layers is a matter of (R U R') U (R U2 R'), but I'm looking for a general way to apply more of the 3x3 algs that I know and find to the 4x4 and higher.