The 'Hundred Year Stone' by Peter Randall-Page
"The Hundred Year Stone is about three metres long and just over a metre tall. When the lake is high, the stone is partly submerged. It appears to have been split by natural forces to reveal a design of ten sections, each making 10 turns, counting out the hundred years of the National Trust's life. Another way to read it is that at the centre of the pattern is the seed from which the National Trust has grown into an organisation as strong and impressive as the boulder.
The achievment of this work is to have enhanced an already spectacular landscape. The boulder clearly belongs here, but the artist has added something, responding to viewers' need to know what is hidden inside the stone and inviting them to wonder how it got there."
http://www.architecturecentre.org/pages/DESIGNS.html