This Pyramid Puzzle was recently featured in a post in Forbes about our Tiny Polka Dot campaign.

Take two suits–that’s 22 cards, with 0 – 10 each occurring twice. The puzzle is to make a pyramid using 10 cards of those 22 cards, so that each number in the pyramid is the sum of the two below it. Here’s a near-solution: every card is the sum of the two dots below it; the only problem is that there’s no third 1 to go in the last space on the bottom.
(Excess cards are on the right.)

I just received this email from a friend who’s been play-testing Tiny Polka Dot with her kids.

“[my daughter] couldn’t make it work [with 10] with two sets then decided
“OK let’s try 9.” Off to verify 10 really doesn’t work”

Here’s the photo she attached with the email (note: spoiler below!)

I actually convinced myself that 10 couldn’t work at the top of the pyramid… for a while. Turns out, I was wrong! More ends up being possible with this puzzle than meets the eye.

But I love this puzzle for precisely the reason that it worked so well for my friend’s daughter: 10 doesn’t seem to work, so she takes a leap of faith and tries 9 at the top of the pyramid; the puzzle rewards the courageous step of trying an even harder puzzle!

Is it possible to put an even smaller number at the top of the Pyramid?

[Sidenote: you can now get Prime Climb and Tiny Polka Dot together at a big discount if you support our campaign. Pledge here!]