A version of Atoms (aka Chain Reaction) for Scratch. Instructions: Taking it in turns, blue starting, place an atom on a tile by clicking a tile with the mouse. You can only place an atom on an empty tile or a tile of your colour. Tiles can take a number of atoms before they 'go critical' and send the atoms to the neighbouring tile - one for the corner tiles, two for the edge tiles and three for other tiles. When a tile 'goes critical' it spills atoms to the neighbours, changing the colour of the other atoms in the neighbouring tiles to your colour. The aim of the game is to end up with all atoms on the tiles being your colour. Background I first played this on the Atari ST, from a cover disc for a magazine. The original was written in compiled GW Basic. A Java version has been written by Neil Fraser, and can be found at http://neil.fraser.name/software/chain This is very much a version 0.1 attempt. It works well enough, but more sounds, better turn notification and better winner checking need to be added. The 'recursion' is implemented using a list as a call stack, for those interested in the implementation method used.