The preceding example works out whether a positive or negative step is needed to move
a variable called currentValue progressively closer to zero. currentValue has an initial value of 3,
which means that currentValue > 0 returns true, causing chooseStepFunction to return the
stepBackward function. A reference to the returned function is stored in a constant called
moveNearerToZero.
Now that moveNearerToZero refers to the correct function, it can be used to count to zero: