D5 · Seeing
One Filter, Dragged Across
Compute a convolution by hand and say what a bright spot in the output map means.
In 1958, David Hubel and Torsten Wiesel listened in on one cell in a cat's visual brain. For hours, spots of light did nothing. Then they swapped a glass slide in the projector. Its faint edge swept across the screen, and the cell went off like a machine gun.