Before revision:  Our proof\etal  is constructive and yields a linear-time algorithm for finding the points .
After revision:  Our proof\etal (2018) presented a relatively simple linear-time algorithm for finding five points that stab D. We present an alternative proof (and the first in English) to the assertion that four points are sufficient to stab D. Moreover, our proof is constructive and yields a linear-time algorithm for finding the points .