Trial design on a piece of dull green slate, bevelled at one edge and incised with scrolls, from Dunadd, Argyll

Trial design on piece of slate, for a penannular brooch, from the royal hillfort at Dunadd, Argyll, 575 - 850 AD

Trial design on a small fragment of slate, from St Blane's, Bute

Trial design on a fragment of thin shale, rudely incised, from St Blane's, Bute

Trial design on a re-used roof slate, with an incised knotwork square, from St Blane's, Bute, 800 - 1000 AD

Trial design on a lead disc, with incised spirals, Pictish, from the Brough of Birsay, Orkney, 700 - 900 AD

Trial design on an oblong stone, broken at both ends, from Jarlshof, Shetland, 1000 - 1200 AD