Many thanks to Tom amd John for their reply.
Delighted to witness the 13:8 example cited by Tom.
These two numbers from the Fibonacci sequence form the origin of our interest in the GOLDEN RATIO.
The following website may be of interest http://www.mcs.surrey.ac.uk/Personal/R.Knott/Fibonacci/fibInArt.html
Last year our open ended study featured the Greek architecture .. this year I thought it may be possible to find Irish sources.
Investigations are continuing
Many thanks
Lila