The built-in implementation of the alligator is incorrect. It uses SMA with altered input parameters to approximate the true alligator indicator.
The alligator was created with a supercomputer to model the elliott wave - it's very apart from other MA techniques. The built-in approximation (and similar techniques) and the true alligator yield very different conclusions. Hence the need for this, a true and exact implementation of "The Mighty Alligator" (Bill Williams, Trading Chaos 1, New Trading Dimensions, Trading Chaos 2).
Note: First script submission. Didn't mean to use this chart. Ugly and messy. Oops.