One of the more impactful rooms you can unlock during your Blue Prince has been praised by critics for its tantalizing approach to gameplay. Centered on the young man Simon, who inherits a mysterious mansion from his late grandfather, the game challenges players to find the mythical 46th room in this 45-room house. You can plan the house's layout yourself each day, drafting one room at a time. The catch is, you can only take so many steps before getting tired, and every night, the entire house resets itself.

It takes some time to get the gist of Blue Prince. Most of its puzzles require you to build multiple rooms, gathering clues and taking careful notes. Solving certain puzzles allows you to unlock permanent fixtures in the house, greatly buffing future runs and allowing you to get closer to room 46. The Laboratory is one such puzzle. Here's how to solve it, and what it gets you in the long run.

How To Solve The Periodic Table Puzzle

Reading The Periodic Table

The key to the Laboratory puzzle is the two copies of the periodic table of the elements that hang on its walls. Don't worry, we won't be getting into any actual chemistry here. Note that one of the tables is mostly blank, with just a few numbers on some of its squares, while the other is fully filled in.

Blue Prince is better when you try to figure things out for yourself. Consider pausing after each hint in this guide to see if you can solve the puzzle with that information.

Take the numbers from the mostly-blank table, and read the squares on the filled-in table in that order to see if you notice anything when you string them together. Use the images above for reference so you don't have to constantly run back and forth across the room.

Reading the elements in order, we get Pu, S, H, Th, Re, Eu, Pa, F, Te, Rn, I, Ne. In other words, "Push three up after nine." You may notice that, in the library, there's a machine with a series of levels labeled with numbers from one to ten on it, including levers for three and nine. We'll come back to that.

How To Use The Laboratory

How To Power The Library

Before we can start flipping switches, we need to turn on the power in the Laboratory. You'll need to build a Boiler Room that's either adjacent to the Lab, or connected to it by a series of rooms that feature ducts. Rooms with ducts include:

• Archives
• Boiler Room
• Darkroom
• Locker Room
• ageway
• Pump Room
• Security Room

In order to activate the Boiler Room, though, you'll need to connect a series of pumps via pipes and valves to turn on the power. See our guide on opening the West Gate for more detail on how to turn on the steam and direct it outward. The basic idea is to connect all three green pumps by turning the pipes between them so that steam can flow from them to the central console, then opening the valves on the three pumps.

Once you've connected power to the Laboratory, you can simply walk up to the of levers, and flip number nine first, then number three. Doing so opens up Blackbridge Grotto, where you can access one offline computer terminal each day and perform its various functions.

How To Use Experimental House Features

Also in the library is a computer terminal, where you can access, among other programs, a set of Experimental House Features. These change the conditions of your run for the rest of the day, and it's up to you to decide exactly how. Each day you turn one on, you'll see a number of statements in two columns: "if" statements on the left, and "then" statements on the right. You may select one of each, and the basic idea is that when the condition on the left is satisfied, the event on the right will occur.

You may be able to access Experimental House Features from other terminals besides the one in the Laboratory.

For example, in the image above, the full statement is "For each bedroom you draft after your second, a letter will be delivered to the Mail Room." In other words, once the player drafts their third Bedroom - and for every subsequent Bedroom they draft - they'll receive a letter that they can pick up by drafting a Mail Room.

This is one of the most desirable effects, as Mail Room letters will often contain valuable clues that are especially helpful to you in the long run. But really, the goal is to decide which of the goals in column A seems most achievable, and pair it with whichever reward in column B seems most useful.

With that, you have all the tools you need to start using the Laboratory. While you can use Blackbridge Grotto automatically from here on out, you'll have to restore power from the beginning if you ever want to use the Laboratory terminal for a second time. Still, with the wide variety of benefits offered by this feature, it's worth trying whenever Blue Prince presents the opportunity.