Connections to product plots?

[hadley]

Can I use similar syntax? How should binning fit into the pp framework? What about smoothing? (Maybe just drawing the top of the bars instead of the lines?)

Density estimates as limits of histograms as binwidth goes to 0. More 2d binning primitives can for categorical. What about for higher 2d?

Existing plots that might fit into the pp framework

• frequency polygons
• pyramid plots
• conditional density estimates
• density strips? use amount of ink to convey density