Chimeras are as Paul says, a fusion between two different embryos very early in development. If one of those is a leucistic Carpet, you can get a Carpet Python which is pied in a sense, but it's a completely different mechanism causing it and it isn't inherited by the offspring. 'Genetic pied' is almost always a simple recessive genetic condition. There are more rare forms of piebaldism. Traditionally, piebalds are any animal with unusual multicolours (it could be a black spot on a brown animal which is usually all brown, for example), but in modern herp usage, it's a genetic, generally Mendelian recessive condition resulting in white areas without pigment and some areas of pigment, usually normal pigment.
Just for fun, here are pictures of some of our chimeras over the last couple of seasons. We've produced quite a good number of them and some turn out quite beautiful. The single snake is one from last season which was mostly wildtype with small areas of marbled. It looked quite similar to the pair in the other picture, but with a much smaller area of pale colour. This male/female pair of chimeras hatched out approximately 50:50 in ration of wildtype to pale mutant colours, and we're very excited to see how it looks which it's the same age as the other one
Most of last season's are sold so I won't post more pictures, but we'll definitely have more to share pictures of this year
In case anyone is confused, no, these are not 'genetic piebalds' in the normal sense used by herpers, they are something quite different.
'True' piebaldism is quite rare in reptiles, there are actually only a small handful of species of snakes with piebalds established in the whole world (Balls, Retics and a small number of others are established, a few more species have had them turn up but for various reasons they haven't ended up established and in the wider hobby), and so far there are no Australian species in the hobby.