Downloading Substrate 1.0.1 for Mac from our website was free. The application lies within Theming Tools, more precisely Screensavers. This free Mac app is a product of Hey Daddio, Inc.
From the developer:
Substrate is a free-to-use fascinating screensaver that looks like cracking patterns in rocks or an overhead view of a growing city. It's fascinating to watch the intricate patterns build on your screen. Some code was adapted from the xscreensaver version.
You may want to check out more Mac applications, such as COM4, which might be similar to Substrate.