Two floors beneath a prestigious local culinary academy is where they keep these human cloning vats. The process is simple: throw a blastulae crispulus into the substrate, induce a low-variation plasma pulse, and then cook it with everyday ordinary fluorescent lights until breakout phase (not shown).
The substrates are colour-coded for ease of identification. Yellow means just pure substrate, red or brown indicates that a human is in the process of being cloned. Green indicates experimental DNA, my guess is NTE (non-terrestrial entity), but my tour guide was tight-lipped on that subject when questioned. The small red taps on the bottom of each vat are fail-safe drains in case the cloning goes out of control. I've heard that a squirt or two of household ammonia is enough to completely disrupt the process, which what I surmise the bottle hanging off the green vat is for: a final solution. Either that or to keep the observation window clean.