This the graph of arctan(qx+ry+s)+arctan(tx+uy+v) for x and y ranging from -2 to +2. It is the output of a neural network with 2 inputs and 2 hidden neurons. A scatter plot, for instance of levels of inflation (with white meaning more inflation and black meaning less) against Fed Funds and Prime Rate could be the input data. The neural network (or you the user) then choose the 6 numbers to make this display match the desired sctter plot as closely as possible. In reality things are not so simple because there is feedback: the Federal Reserve intentionally brings interest rates up when there is inflation. Anyway, the two dimensional case is very similar to something like a very extreme .jpeg compression. Since the six numbers are likely to range from -5 to 5 the whole image is compressed down to less than three bytes of data.