i want to point out, Ñithis bui rtion not vul national but they have commercial uses on the ground floor if these are destroyed, these buildings might collapse a floor, not a huge pile of rubal the likelihood, like in the marina, they come down on the soft story. >> no. what happened in the marina, most buildings got rolled over and crushed the cart. okay. the rest of it stood up. i walked into a bunch of them, you could -- the floors were doing this, but you could walk through the floors but the ground floors didn't exist. >> so we don't want to lose or neighborhood serving businesses as well that's another reason those are important. >> another thing. on a four story building, i can tell you how much that building is going to sway in an earthquake. i don't need to know much about the building, i ask tell you that exactly. if the 2, 3rd and 4th floor are stiff,. >> because they have all the exterior walls. >> the deflexion of the entire building has to occur at the lowest level. so instead of having your whole building leaning over nicely, i this -- upper portion the stiff my knees have