Perhaps the summer magic is the wild potential (more chaotic and uncontrollable) and the winter magic is accomplishment and study and realization (more focused and/or results-oriented, and man I hate using those terms because they both sound dreadfully corporate-jargony, but you know what I mean I hope.)? The Princess Kay sculpture could then be a way of capturing or formalizing the wild-potential magic of late summer harvest in a more disciplined/structural magic related to the coming winter months.

(What goes on in Agnes's -- or any Princess's -- head while she sits for her sculpture, I wonder?)