Download of Hopalong 1.1 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The software is categorized as Theming Tools. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
Hopalong is a fractal screensaver. It generates real plane fractals as described in the September 1986 issue of Scientific American.