In ancient Ireland Ogham Alphabet was based upon the names of trees. (click on this link to see the alphabet). There were 20 native trees. 20 characters in the Ogham Alphabet. Please examine our ogham stone. The words/letters name our school in Irish. It must be read as you climb a tree, ie from the bottom up. Both sides of the right angle (Scoil Oilibheir Naofa). See the useful links page for www.megalithicireland.com/oghamstones.