This is a custom tileset for QFC's roguelike 'Desktop Dungeons'. Use the 'Download' button here to get the .zip file and grab the game for free from: [link]
The tiles have been updated for the latest release of Desktop Dungeons, v1.14 which includes new classes, maps, an expanded religion system and some GUI improvements.
Unzip in the 'tilesets' folder and type 'strain' to select the tileset in the options screen.
Feel free to share.