Tegula is a program for displaying and exploring two-dimensional periodic tilings, based on the concept of Delaney-Dress symbols. Tegula was written by Daniel Huson and Rüdiger Zeller, using code by Klaus Westphal. Tegula is written in Java (12) and uses JavaFX.
A paper describing the underlying math and algorithms is in preparation. Upon publication, the source files for Tegula will be made available here: GitHub.