  This corresponds to transforming the unit square to a rectangle twice as wide and half the height, chopping off the right half, and stacking it back on top to fill the unit square again. (That this transformation reminded mathematicians of baking says something about their unfamiliarity with the kitchen—similar transformations, where the right half is ‘folded’ back on top, are more realistic.) If we represent the coordinates \(p\) and \(q\) in binary, the transformation is this: