Resemblance between central rosette's "towers" and small-plants' "containers".

[MarcoP]

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The idea that the jars might represent the elements is interesting. Of course, a major difficulty is that six elements is a strange number. Four is normal, five appears sometimes, but six seems difficult to explain. 

The four elements are represented as jars (and personifications) in this engraving from Viridarium chymicum, 1624. I am not aware of earlier examples, but I guess they likely exist.
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