The placement functions and the offset function both rely on the variable
which is the index of a given pendulum along the path. There are always an odd number of pendulums,
because there are an even number with a negative index, and an even number with a positive inde, as
well as one with 0 index (the middle). Therefore the index of the first pendulum along the path is
-0.5(number of pendulums - 1). The offset function determines the
(along the parameterization of its path) at which a given pendulum will initialize.