... like a sore thumb

For a while now there has been renovation work undertaken on this building in the centre of Kirkwall.

Now it has appeared all bright and clean from behind its sheeting and scaffording. It has a smart plaque, informing us that it's 'The Ridgeland', dating from the seventeenth century. For almost 100 years, until 1740, it was Town Hall and prison for Kirkwall. It has a window with (the original?) bars.

But I am mystified and distracted by these sticking out stones....