Ian Hamilton Finlay: Mean Terms: Image via artpaperinvitations.
"A 'mean term' is a mathematical concept meaning a term which stands midway between two others. These four mean terms use this concept metaphorically. Sackcloths was worn by the Saints and Martyrs and is sort of emblem of penitence, or of aspiration, of the earthly towards the heavenly"
Ian Hamilton Finlay

Hamilton
Now this is brilliant.!