This is a Parenscript port of the evolve.lisp example from the awesome Land of Lisp (I'm watching the music video again right now :) )
You can see it running here.
Parenscript aims to wrap Javascript, not implement Common Lisp, so I've filled in the gaps with a mess of functions, macros, and JS libraries. It's not very classy; I just wanted to get the code running, so I deliberately resisted the impulse to start building a standards compliant implementation.
Outside the UI, the only change I needed to make to the source code was some minor tweaks to the use of loop (diff). Parenscript has good support for loop, but evolve.lisp hits a couple of incompatibilities, so I replaced collecting with collect, and added from clauses to make Parenscript happy (I'd quite like to work up the PRs for Parenscript if I can ever find the time).