At http://asnoc.wordpress.com/2012/08/02/the-last-of-the-druids-the-mystery… … a book by Ian Forbes, The Last of the Druids; the mystery of the Pictish symbol stones, Amberley Publishing:2012 may also interest readers and members of SIS as this is an attempt to understand the enigmatic Pictish symbol stones, which have been likened to hieroglyphs (of a kind). The purpose and meaning of these has foxed historians, as the symbols clearly have some kind of hidden meaning that is not so obvious in our day and age. Forbes claims they have a calendrical and astronomical meaning and concern the Pictish night sky. The theory is that Pictish druids (if such) were practised astronomers (of the astrological kind) among other things.
You can have a look at Wikipedia I suppose but www.lastofthedruids.com/pictish-symbol-stones/ is a good bet, as well as www.educationscotland.gov.uk/scotlandshistory/caledonianspictsromans/pic… or www.pictishstones.org.uk/pictishstones/pictishstoneshome/aboutthepicts/s…