It seems like we don't make enough time for 3D building. This is a small class of eight students I see with para support. I was worried about "eating" our artwork before we had time to build a structure but there was just a bit of tasting and then lots of engagement. I provided plates of small marshmallows and gumdrops (3 bags gumdrops/2 bags marshmallows) and a box of toothpicks.
Students were encouraged to build up, over and under. This lesson would be effective for K-5 although the older students would probably require LOTS of materials.