 In larger puzzles , the player can also guide the formation of chemicals through multiple reactors , which they place out on a larger rectangular grid representing the planet 's surface . From here , the output from one reactor will become the input for another reactor ; the player is often free to determine what intermediate products to produce to send to the next reactor . The player must not only program the individual reactors , often limited in functionality such as one that can only break bonds but not form them , but plan out the location and order of reactors to make the final product . 
