BlockAPI
From wiki.phychi.com
The BlockAPI allows you to manipulate blocks, the world, and to add new blocks to the game. This article is about how to manipulate blocks, how to make new ones and not about how to access them.
Since the game is only in the alpha, and the block api still developed, I won't write that much here until a beta(=sounds + useable modding and plugin systems) is out.