Roman numerals on upper back

The sundial for the Hallam wedding is finished and I have to tell someone before I lose my nerve. Mr Hallam wanted the date cut in Roman numerals, the old way, with a small dot between each group so it reads like a sentence. I set it out in pencil three times on the slate. Five, sixteen, two thousand and fifteen. Then I cut it, and you know how I am with a chisel when the light is going.

Mrs Hallam came up to the churchyard on Thursday to see it. She ran her thumb along the M's and said they looked like little gates. I told her the numerals were the easy part. A sundial is only as honest as its angle, so I'd set the gnomon to the latitude of the village, and the lettering had to sit where the sun would find it at noon.

Then, with the breakfast sorted and the vicar's wife fussing over the trestle tables, I climbed up to check the bearing with the compass and found I had cut the second group one stroke short. XVI had become XV. Nobody would notice but the sun, and the sun doesn't read.

I left it. Mrs Hallam said it was perfect. At noon on the day it stands in the grass, the shadow falls across the numerals and the dots catch the light like full stops at the end of something. I think I'll tell them about the missing stroke when their own child is old enough to ask why the sundial is wrong.

Your loving sister, Ruth