as you can see here so you break this window pattern a little bit into blocks and that makes it a lot faster or that speeds up i get the speed up almost for free and then they make another approximation in that the way they do this windowing is and now let's just go really briefly so you can see right here that it would be very cumbersome to gather so what we need we're just going to focus this this dotted thing right here is a bit confusing so you want to attend to these things and these you can just get out with a matrix