purple is a good nice number and you're going to multiply those and then you're going to sum them up and then you're going to put that on where the blue dot is okay so where does the information come from in the convolution from around the location from around the output location but in the input okay so you go to the input at the same location as where you want the output to be you take the neighborhood and there is a fixed a fixed scheme of aggregating the neighborhood okay and then you sum you multiply and you sum across it in