We were invited to the Washington, D.C. Family Math Expo earlier this month.

While we can’t travel everywhere and attend every math event (although we do admit that would be a ton of fun!), this seemed like a great opportunity to…

1. Support some excellent work going on in a large and important school district,
2. Play math with a large number of children and families, and
3. Be a good partner within the NAFSCE Family Math network

So we said “yes!”

And I packed my bags, bound for Charles H. Houston Elementary School!

There was time to set up on Thursday. We had three tables: One with 21st Century Pattern Blocks and frames, one with an extra-large mirror book, several puzzles, and a few little things to play with, and in the middle a table for playing with invertible paper strips.

“What are invertible paper strips?” you ask!

Well, if you tape the ends of two paper strips to make, essentially, a 0° angle, then when you combine those strips, you get curvy sided polygons. Because paper is flexible, you can flip (invert) your polygon, turning it inside out and (sometimes/always/never) getting a new and surprising shape.

Mostly we made hearts.

But a few folks stuck around to investigate more complicated shapes. Here are a mom and son who made hexagons in slightly different ways. How would you describe the differences and similarities? How will each look when flipped inside out?

Children puzzled out a finite stage of a Koch fractal.

And they filled all of our hearts with mathy love.

The invertible paper strips were inspired by the 3D printing work of Thomas Gordon Draper, whom we met at the last Gathering4Gardner. We wrote about that experience recently. The Koch fractal frames are a MathHappens staple; the heart is inspired by a Chris Nho/Public Math design. Twenty-First Century Pattern Blocks are a Math for Love product.