<p>Three rats using an orienteering compass, to determine the declination of a wall in preparation to designing a vertical declining sundial. The orientating lines are set along the needle, and the declination can be seen under the white line.
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This wall is  facing 34deg. off due south. The rat has used a set square. Always best to check with a friend
Clem Rutter, Rochester, Kent
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>