they are beautiful aren't they .the top one looks like a sea of ferns.

Beautiful photos Heron, Jack Frost is one of the best artists I know, that's the only answer I could give. Nature has to keep some secrets.

Thank you both, It would be nice if Someone like Magnus Pike (deceased I think) or perhaps Dr Phillip Stott, was to read this, I'm sure they would know.

I 'think' it is something to do with the way water crystalises as it turn to frost

yes it is to do with the water crystals, any dust on the glass and the fluctuation in temperauters as the night progresses. Its like hoare frost formation.

Beautiful designs Heron...:>)

How lovely - I haven't seen ice on glass since I was a child, when our bedroom window regularly had these patterns in the mornings in winter! I remember holding pennies (large ones then) to warm them up and placing them on the patterns to make large circles in them. Snowflakes often look like flowers under a microscope too.