Funny what turns up on HN. You notice these everywhere, if you keep your eyes out. All over the UK and the world on survey points, church spires, old chimneys,

Funny what turns up on HN. You notice these everywhere, if you keep your eyes out. All over the UK and the world on survey points, church spires, old chimneys, apparently random walls - anything that could once have been prominent enough to be a trig point or benchmark [1]. I've bumped into OS survey plates, complete with arrow, in India, Malaysia and Brunei jungle without trying. There must be billions of the things! It used to turn up on every piece of military stores. Every shirt, rifle, bullet, knife, teaspoon, jerry can and tool. There's at least 3 in my kitchen cutlery drawer, and a few more in the garage. :) [1] https://en.wikipedia.org/wiki/Benchmark_(surveying) https://en.wikipedia.org/wiki/Benchmark_(surveying)