Patterning 3.1 adds support for macOS, a free update for owners of Patterning 3. 

With Patterning 3.1, Patterning now runs on macOS as a standalone app and an AUv3 plugin. 

The update is free for users of Patterning, and if you've purchased the app on the iPad the Mac version is free (and vice versa).

Unfortunately, however, there is glitch in the AppStore where it will show the full price on the Mac even if you own the app already.  Just click on the button to buy, and you will quickly be shown this message :

This update is free because you own a previous version of this item. To get this update now, click OK.'

I've already contacted Apple about this, but it seems to be a long standing issue!