Green Mahjong is a HTML5 based GPLv3 solitaire mahjong game. It features three nice themes, six different layouts and works accross all the major desktop and mobile browsers.
The artwork is under the CC-BY-NC license and can not be used in commercial products.
The game can be played in the webbrowser: http://greenmahjong.daniel-beck.org
Green Mahjong in the Google Play Store: https://play.google.com/store/apps/details?id=de.beck.greenmahjong
Green Mahjong in the Apple App Store: https://itunes.apple.com/app/id933634500