Since they're determined by the order of sprites in a .BFT file,
they're best auto-generated by an enum as much as possible.
Part of P0074, funded by Myles.
So apparently, this way of distorting a circle into an ellipse (?) by
adding a value to the angle for one of the two coordinates isn't
actually widely known in math and doesn't have a name. Fair enough.
Funded by -Tom-.