This reading covers structural units, spans, and patterns. Some important units that we should take in consideration would be beams,joist, and columns, bearing walls, slabs and decking. These elements put together can construct a solid well put together peace. There are two different types of systems there are one way systems and two way systems but two way systems are more effective there supported by four columns which defines a horizontal layered space. The length of the horizontal element depends on the vertical support. There are also patterns that are made up of a grid. Grids that you can make different varieties of. You can make regular, irregular and even rotations. Forms of stability are knee bracing, K bracing , cross bracing. There are rigid frames bracing frames and shear walls to hold up.