Former U.S. memory champion Joshua Foer reveals how he uses his "memory palace" so he can memorize the first hundred digits of pi — 3.141592, and so on — in a recent WIRED video.

Foer’s memory palace is where he puts images inside a space, so he can remember huge quantities of information later. After pi, Foer can put images that help him remember decks of playing cards, lists of hundreds of words, and even entire poems. But if we’re looking specifically at pi, it’s more than just remembering 100 numbers.

Instead, Foer teaches us how to use his "major system," where numbers zero through nine equal one or two letters. This system allows you to convert any number into a word and then into an image you can later visualize in the memory palace. So, for example, if the number is 41, four equals R and one equals T or D. The image could then be a RaT.

Memorizing pi requires people to use this major system in three-digit chunks and come up with a unique image for each chunk. If you’re looking at 141, it translates to DRD or a DRuiD. The next three digits, 592, are LBN, which could be LiByaN like Miammar Gaddafi. By the time you get to the hundredth digit, you’ll have 33 images ready to be placed in the memory palace.

Watch Foer himself put it to the test in the video above. And for more on how you can improve your memory, click here.