I need to store data to represent this: Water + Fire = Steam Water + Earth = Mud Mud + Fire = Rock The goal is the following: I have draggable HTML divs, and when <div id="Fire"> and <div id="Mud"> overlap, I add <div id="Rock"> to the screen. Ever played Alchemy on iPhone or Android? Same stuff Right now, the way I'm doing this is a JS object : var stuff = { 'Steam' : { needs: [ 'Water', 'Fire'] }, 'Mud' : { needs: [ 'Water', 'Earth'] }, 'Rock' : { needs: [ 'Mud', 'Fire'] }, // etc... }; and every time a div overlaps with another one, I traverse the object keys and check the 'needs' array. I can deal with that structure but I was wondering if I could do any better? Edit: I should add that I also need to store a few other things, like a short description or an icon name. So typicall I have Steam: { needs: [ array ], desc: "short desc", icon:"steam.png"},