When I heard about the Parkland shooting, one of the things I heard was that some of the shooter's bullets found targets on the other sides of the building's interior walls. That surprised me because I very distinctly recall the walls at my one school I attended, my elementary school. The lower floors walls were cinder block and the upper ones were brick covered with plaster. I remember that because one of our classroom playtime activities was tossing balls -- generally tennis balls -- against the wall and playing dodgeball in the halls. Indeed, one could do all manners of things in one classroom and, but for a door being opened, nary a word was heard outside it. In PE class, the walls were used lots of times for all sorts of things. Of course, the walls at M. Stoneman Douglas are drywall rather than masonry, and I certainly don't know what material forms the interior walls at my or my kids' high schools. Having now thought about it, it's clear to me that I shouldn't be surprised that interior walls are drywall; it's certainly a less costly way to form a space divider. I guess it's just one of those things that hadn't struck me as having changed in school construction....not that before now I've spent any time actually pondering modern school building construction. Maybe, however, in light of the push to make schools safer, it's worth considering building schools from more durable materials than drywall?