The research I've done for my PhD involves designing and implementing a new language, which computes by concurrently reducing trees (using a form of tree-rewriting) which sit together in tree-spaces (bags) and communicate amongst eachother (exchanging parts of themselves, in Linda-like fashion). The language is 100% graphical and linear as well. My thesis on this topic: (pdf, 1310k), and the first public version of the implementation (zip, 367k). I have removed all papers at the bottom of this page as they are all superseded by the thesis. And now… some confusing pictures:
This is an actual screenshot of the beta implementation (written in Java, and compiling to JVM code). This is how I imagined it would look before I implemented it. Here are 3 more (very old) mock ups, included only for completeness sake: 123.