The squares are paint chips from Walmart :-)
I love having this on my cabinets! Not only does it display the birthdays (I wrote each name and birthday on a square after taking the picture), but it gives the kids constant exposure to graphs. It will be so easy to introduce them to graphing throughout the year by asking them questions about the birthday graph. Which month has the greatest number of birthdays? Which month has the least? How many more birthdays are there in September than in February? I can't believe we don't have any birthdays in June, July, or August! I was a little sad that I didn't get to use any purple, blue, or red squares! Oh well...I'm still really happy with how it turned out!