I taught a second lesson using the 3-D models. This lesson was on contour lines and gradients, and again was sourced from [here]. The students used rulers to find points at different heights and draw contour lines at those heights, and answer prepared questions using them. This lesson would probably be better earlier in the semester, when they are first learning about contour lines, but the materials weren’t ready in time. However, it seemed to cement their understanding of the concept when they drew the contour lines on the chalkboard, making the transition between 3-D and 2-D. I then showed the solution provided by the writers of the lesson, so they could compare their contour maps with the ones created by the computer. Most were a pretty good match.