Pixel Bar Charts
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A visualization technique for very large multi-attribute data sets.

Hanrahan: "mix your metaphors"

Pixel bar charts combine: bar chart metaphor, scatterplot metaphor,
pixel-per-value metaphor.

Bar charts show only a small amount of data.  Scatterplots often
have a lot of overlap.

Pixel displays lack pixel-coherence -- if high-contrast pixels are
mixed together, perceptual system blurs away detailed colours.

Try equal-width bars... equal-height bars.