# How to Build a House of Cards

August 25, 2014

Everyone loves card games, but it can be difficult to find a card game that everyone wants to play. However, most people are intrigued by the concept of a house of cards. Building a house of cards is challenging and fun, and the resulting structure — no matter how big or small — is a thing of beauty.

## How to Build a House of Cards

One of the simplest types of card houses is a triangular pyramid, made up of identical smaller triangles. To form a basic triangle, lean two playing cards against each other, with their tops touching, to form an inverted letter V.

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Once you feel confident about creating this basic shape, it’s time to build a 2-level pyramid! First, build 2 basic triangles, side by side. I like to space the bottom triangles evenly so they are slanted at the same angle. One easy way to do this is by laying a playing card underneath or in front of the triangles.

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To build the next level, carefully build a third triangle on top of the first two. Carefully balance a playing card on top of your first two triangles. This forms the bottom of the third triangle. Then lean two playing cards against each other, with their tops touching, to form an inverted letter V.

With a steady hand and lots of practice, you’ll soon work your way up to a 3-level pyramid and beyond!

Once your card house is done, step back and admire your work. Ask your child to count the number of triangles in the pyramid.  Don’t forget to count the upside down triangles, as well as the larger triangles formed by the smaller triangles!

Now ask your child to count the number of cards in each level. Can he or she work out how many cards would be needed for a 3-level pyramid? How about a 4-level pyramid? Older children will notice that the number of cards in each level increases by a factor of 3 — the top row has 3 cards, the second row has 6 cards, the third row has 9 cards, and so on. The number of cards in each level can be written as the numerical sequence {3,6,9,12,15….3n}, where n is the number of levels.

Card stacking is notoriously tricky, and it’s all too easy to give up in frustration. Here are a few tips to help those cards stay up:

Most playing cards are coated with a glossy finish to make shuffling and dealing easy; unfortunately, the slippery surface makes it difficult to stack!  Look for old cards whose finish has worn down, or look for the least glossy finish you can find. Guinness World Record Holder Bryan Berg uses Cartamundi’s Ace Brand and the US Playing Card Company’s Pla-more line. Use the stiffest, straightest cards in the pack.

### Build on a Rough Surface

When it comes to card stacking, friction is your friend. It’s difficult to balance cards on a slippery surface, so beginners should always build their card houses on a rug or carpet.

### Be Careful

Try not to touch the rest of the cards while you’re stacking.

### Be Patient

Like anything, building a card house takes practice. It’s not uncommon for one or two — or all — of the cards to fall while you’re stacking. Keep trying!

Want more card math? Check out Bedtime Math’s House of Cards problem!

Photo courtesy of Ana Picazo