described is you know one layer of one of these spas feature learning algorithms maybe sparse coding may be as possible to encoder may be a sparse VPN or sparse RBM and turns out what you can do really building on a jet engines work what you can do is recursively apply this procedure where instead of just going from pixels to images excuse me pixels to edges you can recursively apply this procedure and you know just as you can group together pixels to form agency can group together edges to form combinations of edges and group together