  We provide an algorithm for computing the Euler characteristic of the curves
$S_p$ in the space of cubic polynomials, consisting of all polynomials with a
periodic critical point of period $p$. The curves were introduced in [Milnor,
Bonifant-Kiwi-Milnor], and the algorithm applies the main results of
[DeMarco-Pilgrim]. The output is shown for periods $p \leq 26$.
