Last May I posted about how I presented photos from the city to have fourth graders talk to me (and, more importantly, to each other) about parallel, perpendicular, and intersecting line segments. The photos I took I included in this post:

http://mathforum.org/blogs/suzanne/2013/05/18/parallel-perpendicular-intersecting/

On a follow-up visit to that 4th grade classroom, I took some photos in their classroom. At first I just wandered around taking a photo of this and that but soon different students caught on to what I was doing and suggested things I should photograph. The most fun was when the “climate control” young man turned his back to me indicating I should photograph his shirt! He was usually focused on the discipline issues of one student assigned to him but that day they both found themselves engaged in mathematical thinking!

click on each image to view a larger version