Unless you want a mess, usually you still separate by both. Just because you "cut" a square vertically or horizontally, doesn't mean each strip doesn't have, s

Unless you want a mess, usually you still separate by both. Just because you "cut" a square vertically or horizontally, doesn't mean each strip doesn't have, say, more separating lines that you didn't cut. These concerns should still be separated, even if they aren't separated at the highest levels of your application. At the top level, we slice our projects vertically (by feature) at work. But it doesn't mean we have 1 giant god framework that handles all layers for a given feature. We still segment by layer. And we still have layer focused libraries.