Today I discovered Machinations thanks to this excellent Gamasutra article. On Machinations Wiki we can read that: "Machinations is a theoretical framework and an interactive, dynamic, graphical representation that describes games as dynamic systems and focuses on closed feedback loops within them. The intention is to find a way to express and investigate (recurrent) game structures methodologically. Machinations offers a new lens on the intuitive and delicate practice of game design and balancing. (...)". The tool is part of a PhD thesis by Joris Dormans, and it's lovely.
As my first experiment I tried to re-create a simple RPG game, at the macro level. In this abstract game diagram you can : kill enemies, level up, upgrade your stuff, die and revive, and trade gold for health.
Please note that Machinations was not created to play games, but to discuss game design and prototype game mechanics. So you might find yourself a bit lost when trying to play this :)
Anyway, to play this abstract RPG game diagram, just clic on the Run (R) button on the bottom left corner :)