I thought the inspiration was largely plants, wheat in those pics. 

the ice has some nice patterns though.

summac.....

"eye music"

according to FLW Trust, the sources "range from the Froebel gifts of his childhood, to Louis Sullivan’s flat ornamentation, to the designs of the Vienna Secession...touched by the autumnal dashes of his color palette".

 Thanks Nam Henderson

After looking at some of Sullivan's ornamentation on this  site it seems as though FLW was very inspired by Sullivan's designs. Door at St. Nicholas Hotel   Grill at Chicago Stock Exchange   Kick Plate at St. Nicholas Hotel  St. Nick Skylight   St. Nick Window #1  St. Nick Window #2  FLW was working with Sullivan at the time of the St. Nicholas Hotel construction so I wonder how many of these designs came from Louis or Frank. If they came from Louis Sullivan now we need to find his inspiration.

Here are some textile designs from the Vienna Secession movement. And here is an interior picture of the Austrian Postal Savings Bank by Otto Wagner . I see some FLW in the floor design and in the textiles. It is amazing where inspiration comes from. 

The Savings Bank is interesting in that it is designed around a Basilica footprint with a nave and aisles. Was this his intention or influence?