 if you're going to do an efficient building that's going to be able to compete in the market you usually want a double loaded corridor which means a corridor with units on both sides of it because you don't want to build too much common space that you have to heat and construct but you can't rent so if your building is too wide to not allow you to do a double loaded corridor it's really hard to do residential so that's why a lot of malls big blocky square spaces