Hamming Distance shows the erratic behavior of the usual hamming distance in the space of small bitmaps. This space is a product of single-bit spaces that are just too small. The hamming distance in Prod(i=1,n,Xi) behaves much better if the spaces Xi are not too small.
Feature Detectors illustrates how cells that are tuned to edges at various orientations may arise in the visual cortex. Although the model is crude, it does not require carefully crafted connection topologies and delicate adjustments. All that is required is some concrete implementation of a Pattern Engine that will grow random germs of functions under the influence of sensory data.