Adventure Quest Worlds
Adventure Quest Worlds is an online RPG game, which works in browser. You can create your own charater and discover huge world of the game completing many quests. You can put in it various cloths and weapons. Even more, you can buy your own house in the game and equip it with necessary furniture.
There's zone Chiral Valley in the game which is inspired by Escher's artworks. There's location with impossible waterfall based on Escher's lythograph Waterfall. Also, you can see the impossible staircase and the Moglin tesselation on the wall in the Ruins.