The Rosettes in Biblical mythological interpretation

[R. Sale]

I'll have to go with the flame interpretation also. In fact it could be argued that this is a simplified version of cosmic boundary of the flame-based variety, rather than the more common cloud-based variety. The same sort of substitution of simple for complex that occurs in the VMs cosmos (f68v3) with the nebuly line vs. the BNF Fr. 565 cosmos.

There's a good example of a fire-based cosmic boundary in the Bedford Hours. And it's French and VMs C-14 contemporary. Not to mention the Duke of Burgundy.