One of my favorite activities I did regularly with my 2nd graders in the past couple months was inspired by Christopher Danielson’s “Which One Doesn’t Belong?” posters.

### These are an incredible resource! Find them here.

The posters came in a set of 8 – a perfect amount for us to explore one per remaining week of school. I found some unused magnetic name tags and decided on this set up.

I had no idea what was going to happen – I gave no verbal directions (only vaguely pointing out we had something “new” in our classroom). It took a couple days, but students did start to engage.

**Each week, I would put up a new poster on Monday and we would have a whole-class discussion about our ideas on Friday.**

As we continued with this routine week after week, students’ reasoning became more sophisticated and their engagement increased as well – students would sneakily move their name to a shape during circle times and transitions. They would congregate around the poster, asking about and pushing back on each other’s choices.

## Here are some of my favorite noticings and conversations we had.

- The top right hexagon can be turned into a drawing of a cube by drawing three lines. (Do you see it?)
- The other three hexagons can be “squished” a bit to all look the same. (What does this tell us about angles?)
- The top left shape (in the poster on the right) could be straightened out into a very long, skinny rectangle.

- What is a shape? Are letters shapes? Is everything a shape? Do all shapes have names?
- What is a polygon? Can we come up with a definition from this poster (below)? Could we explain it to a Kindergartener?
- Ideas – a polygon might be: a shape with a lot of sides, a shape with at least 4 sides, a shape with any number of sides that are “line segments”.

## Now for some questions moving forward…

- How might you use these posters in your classroom the whole year? With younger kids? Older?
- How might you support students to create their own WODB images, perhaps moving beyond just shapes?