I found myself strangely taken with The Garden of Cyrus, which makes only a minimal appearance in the Preston book: it’s not really a text which can be excerpted meaningfully. Browne starts with the idea of the quincunx; but the quincunx seems more a useful excuse for digressions than the mystical pattern he promises at the start. It’s a pleasant essay if one’s willing to wander along behind Browne; reading this, one immediately realizes from where Gass found his form for On Being Blue.

That’s a perceptive statement on Cyrus assessing it accurately. The clue is in the dedicatory epistle (looking in my 1658 edition) is the sentence –

Subjects so often discoursed confine the Imagination…Besides, such discourses allow excursions, and venially admit of collaterall truths, though at some distance from their principals.

Your observation precisely !

I don’t know the Gass you cite but are you sure he read and was influenced by Browne’s Cyrus?