from the rather-than-scrabble-tiles dept.
tim writes "Recent work at the Salk Institute in La Jolla, Calif. shows that cells in the retina sample visual space like a multi-layered jigsaw puzzle. High resolution measurements of light response reveal that individual cells have irregular shapes, but together their shapes coordinate to tightly cover visual space. This type of large scale, exquisite coordination could be a general organizing principle of the brain, but no one has seen it previously because technical obstacles typically prevent recording from large cell populations." Here's a link to full paper.
We warn the reader in advance that the proof presented here depends on a
clever but highly unmotivated trick.
-- Howard Anton, "Elementary Linear Algebra"