You gotta decide which story to take at face value, though. In some versions it's only one layer of wood of unspecified shape and arrangement. In others it's

You gotta decide which story to take at face value, though. In some versions it's only one layer of wood of unspecified shape and arrangement. In others it's layers of wood at regular intervals. In others it's specifically square-cut timber. Generally the more recent retellings of the tale have more of these juicy details than the older ones. The thing about a good story is, it's hard to resist the urge to make it even better.