From Don's facebook conversation with Barbara, his student from 31 years ago, about the pyramid her daughter Maggie made

Barbara: Mr. Cohen, I felt like I was channelling yesterday when Maggie and I got involved in figuring out how many pieces there were in the huge lego pyramid she had built.  My favorite part was when she realized that there was a quicker but less interesting way to do the calculations, and she said, "Let's do it the longer way!  It's more fun!"

I posted a photo of the pyramid and tagged you in it. I'm not sure if it's readable, but that white piece of paper says "10,404'.

Donald Cohen: your pyramid is a marvel, Maggie! It looks like an Egyptian pyramid. I like the idea of doing something the longer way too, but more fun in the process. Is the pyramid made by the squares of even numbers? Like 2^2=4, 4^2=16, 6^2=36? 

Jennifer Olinger (a friend): Wow! That's impressive! Is that number (10,404) the number of Lego bricks she used?

Barbara: "Not the number of bricks, the number of dots. A spontaneous unschooling math project. I posted it to share with my beloved childhood math teacher".

Barbara: "Mr. C, the bottom square side is 48 dots across, with each layer above being 4 dots shorter. We started by figuring out 48 x 48 (which in and of itself was new, since M. had never done double-digit multiplication), and then 44 x 44, and then 40 x 40 (easy!), and then used those three numbers to predict what the next one (36 x 36) would be without doing the multiplication. I have to run now, but I'll send you an email with the details.. And emailing or skyping with Maggie would be amazing. I was just about her age when you taught me two important things: (1) math isn't just arithmetic, and it can actually be fun and (2) that I'm actually pretty good at math! I can't imagine anything better than Maggie getting to get some Mr. Cohen math magic. I'll email you asap!"

Thank you Barbara, for sharing Maggie's work with me!