I built them by buying a tray of desserts from Costco. It didnt taste that great, but maybe my tastes arent that sophisticated, and washed them out, drilled holes, and glued waterproof magnets onto them. Tada!
I went to the Unique Coral Facility and my wife and I got a private tour and they gave us a sample of some deep sea coraline. Pretty cool huh? Just like the purple stuff but everyone has that, mine always strikes conversations...and usually giving them one of my coralline encrusted snail.