@jensimmons In all this discussion of expanding / generalizing the layout properties, has anyone discussed integrating a block flow layout (in the sense of display: flow-root, ordinary paragraph flow) in one direction with a more controlled layout in the other?

That's another thing I've often wanted: to be able to make an item that's positioned vertically in the paragraph flow span or float into sidebars / margins.

With some of the masonry proposals, that seemed a reasonable future extension.