In Grace Avery's Petri Lab, you'll be greeted by quite possibly the friendliest batch of germs on earth. They even play by the all the rules! The green germs always duplicate what's on their right, and four blue germs turn into one silver germ, and four red germs turn into three yellow germs, and AAAAUGH SO MANY RULES! It'll take a generous helping of logic and patience to sort the germs out in the puzzles this game dishes out.

As a professional germ wrangler, your goal is to arrange the germs in each Petri dish to match the target at the top of the screen. Each colorful germ has a specific ruleset it follows; you can view the rules associated with any germ by mousing over it. Click on a valid germ to execute its corresponding rule. For example, clicking two adjacent yellow germs will delete themselves, while clicking a group of six yellow germs will transform them all into one green germ. However, with rules regarding quantities of germs, you have to have the exact amount, or else the rule will not be performed; four yellow germs gets you nothing. The key to this game is to figure out the order the rules should be performed in, as one rule may effect your ability to execute another rule later on. Can you get the germs to line up using the power of the agar rulebook?

Play Petri Lab