This modular terrain is for our OpenTactics project. If you're familiar with Pocket-Tactics, it runs on a very similar system except that the maps are blown up to scale with the characters (as shown here). We'll be releasing a beta set soon, along with fully customizable rules options so you can make your own characters, monsters, vehicles, et cetera, and share them with the community (as well as use this system with any gaming miniatures). These tiles are sized to our 18mm scale character models, and will work well with any system that allows for grids (including Dungeons & Dragons and Pathfinder). If you happen to be interested in play testing and/or designing for OpenTactics, shoot me a message.
We've set up a Patreon page for anyone who's interested in helping to fund us so we can keep making free and open sourced games like Pocket-Tactics, Discord, and others, not to mention the growing catalog of gaming miniatures that you can use for whatever you want! (Psst... we take requests and commissions...)