Four half-men awkwardly holding hands inside four concentric bands.

[nablator]

In earlier copies of the text, like this one You are not allowed to view links. Register or Login to view. which I've just browsed entirely, that illustration is absent. So perhaps the txt is not too singificant, just the idea of 4 seasons.

I suppose the seasons illustrate Liber de temporibus. The "quadrifario opere dei" is something else, heavy theological stuff interpreted from Genesis.