[zerovox]

> We also require every access to any stack variable to do math to figure out where on the stack it's arguments are.

In the article, it appears to be the opposite. Previously this math was required (`[ai] = 2 + parameter_count - i - 1`), but by reversing the arguments in the stack it's now always a constant offset, and they prevent indexing out of the passed arguments in the frame by ensuring there's at least as many arguments as formal parameters by stuffing the call with extra `undefined`s:

> But what happens if we reverse the arguments? Now the offset can be simply calculated as [ai] = 2 + i. We don’t need to know how many arguments are in the stack, but if we can guarantee that we'll always have at least the parameter count of arguments in the stack, then we can always use this scheme to calculate the offset.