Livre d'Or

I think you might be mistaking my point about non-prototypicality; it's not about how expansive your definition is, it's how it's structured.

One of Lakoff's (linguistic) examples is motherhood; we're (reasonably) happy with the idea of mothers who didn't give birth to their children and who aren't genetically related to them, we're also happy with the idea of mothers who only did that (e.g. a mother who dies in childbirth). One explanation for this is that you have the idea of a prototypical mother who provides both DNA and nurturance to a child, and various variants on this pattern also counting as mothers. For a more neutral example, see climbing - you have a notion of clambering (i.e. achieving vertical movement by grabbing onto things) and ascent, so "the bear climbed up the tree" would be prototypical, "the bear climbed down the tree" and "the aircraft climbed to 10000 feet" would be valid but nonprototypical and "the aircraft climbed down to 10000 feet" would be a misuse of "climbed" - it seems wrong to me, at least.

The part of my mine that thinks geometrically has just come up with "star-shaped" vs "rectangular" definitions.