It turns out this thing's called an "Inogon leading mark" or "Inogon light" -- Inogon, not Inogen -- and it's a Swedish invention from the 1980s. But there's still a question: why is being used to mark an undersea cable, instead of guiding people home?
A tick stick is used to quickly and preciously copy and make a pattern of any odd or complicated shape where using a ruler would be challenging. The ticking stick was made popular by boat-builders and is a way of measuring accurately which has been around for centuries.
Extracting metallic iron in your breakfast cereal.
