Spot-It – How’d they do that!?

During the holidays, you might have heard of the popular party game called Spot-It. The goal is to match certain elements on two different cards as fast as possible. It’s a great game for all ages and may challenge the adults even more than the children. (At least that was the case for us.)  What you may not know is that behind the cards is a really awesome math game!

Spot it! Tin (Hint: It's really a math game!)

Spot it! Game

While playing on New Years with my family, I was intrigued by a note on the package. Each of the 55 cards has “one and only one” common element with every other card! How’d they do that? Since each card contains 8 pictures and there are 55 cards, it hardly seems possible that this could be true. But it is. A thorough investigation by yours truly (with the assistance of a very supportive 4-year-old) made sure of that.

A thorough description of the math involved can be found here (in French).  If French math papers aren’t your idea of fun, the wonderful people over at StackExchange have provided a Python implementation of an algorithm that will generate the appropriate sets, but even this is a bit tricky to follow.  I enhanced the solution given by Neil G. to include PDF output files with numbered cards that can be printed out and cut into strips to verify the solution.

The Python code can be found here and is worth reviewing if you’re interested in that sort of thing.  If you’d rather just skip to the end, the PDF files below contain solutions for orders 0, 1, 2, 3, 5, 7, and 11. (For reference Spot-It is order 7 [which means 8 items per card].)

Spot It – Order 0 (4735 downloads)

Spot It – Order 1 (1540 downloads)

Spot It – Order 2 (1368 downloads)

Spot It – Order 3 (3299 downloads)

Spot It – Order 5 (4925 downloads)

Spot It – Order 7 (6002 downloads)

Spot It – Order 11 (2054 downloads)

Spot-It Cards - The best math (card) game ever!

4 cards means a total of 6 comment elements.


UPDATE: This page has received much more attention that I ever expected.  A popular question is “Could you build a teaching tool to make a card game like Spot-It, but with ‘sight words’ ?”  The answer is yes, and I’ve made a start here.  The Excel spreadsheet linked below uses some simple functions to build cards, and the Google Docs version shown here (in Czech) extends the idea even further to include images.   If you have made, or know of, an improved version please let me know and I’ll update this link.
Spot It Sight Words (3340 downloads)

For even more resources, check out  They have created lots of free tools to help homeschoolers, teachers, and parents teach sight words to kids from Pre-K to 4th Grade.  Awesome!

SightWords logo


38 comments on “Spot-It – How’d they do that!?
  1. Thank you for PDFs (great for non-coders).

    One question:
    Is it possible to have lesser # of cards in a given solution above (eg can order 3 have 12 cards instead of 13 and still give the same variation) ?

    • Sure. The beauty of the math is that you can throw away (or lose) as many of the cards as you like and still have a viable set. Geometrically it means that there are holes in your mathematical surface, but your average player would never know.

  2. I’m wondering how to create a custom set of cards. I see that you have, for the numbers listed in your pdf files. Yet I would like to use the system to make learning sight words more fun. Do you have an Excel file that one could input the items (sight words in my case) and pop out the “cards” such as you have here.

    • Wow! What a great idea. I don’t have something like this in-hand, but I think I know how it can be done. Give me a few days and I’ll post whatever I come up with.

    • Actually, that was easier than I expected. The Excel file below contains one solution for Order 4 (13 cards & 13 words). The same spreadsheet could easily be expanded for more words if you wanted to do that. All I did was cut and paste the text out of the PDF files and then use the “VLOOKUP” function to translate the numbers 0-12 into the words in Column C.

      Enjoy, and let me know if this is useful for you.

      Spot It Sight Words

      Also, thank you to Mrs. Perkins for her list of sight words

  3. I have no idea who you are but today you are my hero. As a former math teacher turned homeschooling mom to emerging readers, I was determined to construct an algorithm to make sight word Spot-It cards. Now, I don’t have to put any mental effort into it; thanks to you!

    • You just made me cry! :`) We are a homeschooling family ourselves and it makes me happy that others find some of these tools useful. (I’m also happy any time I hear about a “former math teacher turned homeschool mom”, we need more science-types in the homeschool community.) If you expand on the idea, please share it with us, and you are more than welcome to post links.

  4. This is helpful, but I still can’t figure out the algorithm for 36 cards for both a 5 (or 6) order set, and a 11 (or 12) order set. I have spent hours on it. I have studied these PDF’s, and plotted out 36 cards, but fry my brain on it. :-( help!

    • I know the feeling, the math hurts my head too. Have you looked at the Python code on GitHub? That might help explain things a little better. Also, the algorithm presented there is only valid for “prime orders” (E.g. [0, 1, 2, 3, 5, 7 , 11]).

  5. Thank you so much! We were hoping someone had shared an algorithm. Part of the challenge of the game is the different sizes and orientations – big and small. Is there a way to code the shapes B or S so we get them to be like the actual game?
    I was thinking of buying a new game and documenting the sizes to your chart, but is there another way to do it?

    I’m trying to make a template that teachers can drag and drop clip art onto labelled fields to make a perfect game.

    Hope I explained that legibly!

    • Hmmm… Sounds like a good idea, but I’m afraid I don’t have the time to work on it at the moment. If you come up with something please feel free to post a link to it here.

      • I am interested in this game for teaching ESL. Variations in size, color, and orientation (as wll as number of images) obviously affect whether the game is faster and easier, or more challenging (slower). The game as is seems a good mix, so my gut is to stay with what they’ve done. Each umage is always the same color, and this seema to help speed. (One strategy is “look first at black things, than at yellos things, etc.) Images are generallly oriented pointing “up”, towards the center of the circlen with one image in the center. This yields more or less random differences in orientation from the point of view of any given player, I would think. Sizes are quite various. Of eight images of the clover, for example, I see one humongous, one big, two medium big, two medium small, one small, one tiny. It is not the case that each card has systematically one humongous, one tiny, and the rest middles. It would be interesting to know if cognitive scientists have taken any interest in this game, and could say whether all these variations in size are really worth building into the game, but I suppose the blue orange people did product testing. Any thoughts, reactions, greatly appreciated.

        • Hi Don. I’ve noticed the same variations in size in our game as well and wondered if that had something to do with why I can sometimes stare at a card for what seems like minutes without finding the match. I’m not aware of any “cognitive science” studies using Spot-It, but I’d be very interested to read them if someone else could provide a link.

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    • First of all, I used Google Translate to read your post so I might have missed some things.

      Second, WOW! I thought it would be much harder to incorporate images into these cards. Way to go!

  8. Pingback: I made a Spot-it Clone – Aaron Barker

  9. I have created an online generator of Spot It games where you can provide words or images and the cards are created for you. The PDFs you provided here were the whole reason I was able to make the site, as there was no way I could figure out the logic myself.

    Thank you so much for providing the PDFs, hopefully the generator will be of interest to those who visit this page as well.

    Blog post about it:
    The game maker itself:

    • Wow. I’m honored. Thanks for going so far above and beyond my meager efforts. I can’t wait to create our own ‘Family Edition’ for the holidays!

  10. Hello,

    I am trying to make a spot it game with the excel sheet that is provided on here however I want to add more pictures then the 4 allowed on the excel sheet can someone tell me how to do this? I am using these words in the excel sheet to know where to put the images could someone explain this for me? I would love to use these with the kids I work with!
    Happy Angry Sad Frustrated Scared Surprised
    Shy Sleepy Embarrassed Proud Silly Disappointed
    Confused Grumpy Excited Sneaky Bossy Mean
    Nervous Impatient Curious Kind Jealous

    • Well, sometimes it takes longer than others to maintain this page. I apologize for the delay. The idea is that that “Word List” in Column C (cells C12 through C24) can be updated with anything that you like. Once you’ve populated it with the words that you want, cut & paste the “Cards” out of columns L through P.

      The spreadsheet is “Order 3″ and works for 13 cards and 13 separate words. If you have more than that, you’ll have to make 2 separate games, and then be sure not to mix up the cards. 😉

  11. Thank you and thanks to Aaron Barker for the logic, pdf files, and card generator! We are homeschoolers and one of my daughters and I are learning Japanese together. We love playing Spot It and while playing a few days ago I thought what a great memory tool it would be for learning kanji (Japanese characters) — practicing them is always tedious for my daughter. Thank to you guys, we just played our first game! So much more fun than flashcards! Just thought you might be interested in hearing about another way this can be used.

    • Wow, that is totally awesome! The creativity that has been displayed here is incredibly inspirational and encouraging to me.

      And kudos on learning Japanese… May your ambition only be exceeded by your success!

  12. Hi, and thank you very much for the algorithms!

    I’m making a spreadsheet which can create custom cards and would like to incorporate Order 11, however the numbers on the PDF file are often cut on the right side. I tried changing the font size but had no luck viewing the missing numbers. Would you be able to publish another version in smaller font where all 12 numbers in the algorithm can be displayed?

    Once I complete the spreadsheet, I’ll gladly share it with everyone!

    • Thanks for pointing this out. I just uploaded a revised version of the Order 11 cards that uses a smaller font. Can you check this out to make sure that it works better for you?


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  14. Have you seen the other similar game to Spot It called Fast Flip? It is made by the same company. Does that game use the same principles that you have in this post?

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  17. Hello William,
    First off I want to say thank to make the excel/doc file to make the game easier for people like me. I’m graphic design and making a custom Spot it game But my designer mind in unable to make it happen. :(
    I’m having 23 symbols and I want to keep 5 symbols on each card.
    What should I do now? Please help me to find the correct equations for this.
    I don’t know python and how I can use that, so I used Excel and Doc file only.

    Thank you so much in advance.


    • Hi Vicasso! The number of cards and the number of symbols on each card are kind of important. 5 symbols per card doesn’t work for this algorithm (Order = 4), because 4 isn’t prime. Sorry. :( -William

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