microdots

Police are also using forensics to track stolen sheep, while Cumbrian sheep and beef farmer Pip Simpson has trialled coded microdots on the sheep's fleece to brand his sheep.

Tradespeople may also install covert cameras in vans, apply forensic marking products such as microdots to their tools, and label them as protected, for example.

Those looking to understand the roots of San Francisco psychedelic rock need only read one observation from Paul Kantner, who died Thursday at age 74, to connect the microdots. 

There was also steganography, the art of shrinking and concealing information inside objects such as microdots, usually only detectable by those who knew exactly where to look.

Lonsdale communicated with Moscow through a radio transmitter hidden at Cranley Drive and photos of documents were reduced to microdots and sent abroad inside antiquarian books.