I've been using Clip Paint Studio Pro, a photoshop-like program that's built with art as its primary intention, rather than an adaptation made by users. It's got a lot of features that Photoshop doesn't, and one I've been really excited about is the reflection ruler, which allows you to set any number of reflections.

Radial patterns are so much fun! With this one I made the central image, then I duplicated it to tile the image, then I made some adjustments to a few spots, for variety.