The earliest known drawing in human history – a red, cross-hatched pattern that looks somewhat like a hashtag – has been unearthed on a rock in South Africa.

The earliest known drawing made by a human has been found in a South African cave and it looks very similar to a hashtag, the grouping and search feature made popular by the Jack Dorsey-led Twitter.

Blombos Cave drawing with ochre pencil on silcrete stone. Craig Foster. The crisscrossed pattern, drawn on stone 73,000 years ago, wasn't used as shorthand for #artlovers, but the hashtag-like ...

Learn to recognise different circuit symbols with these interactive learning resources for KS2 Science students aged 7-11 from BBC Bitesize. ... Symbols are simplified drawings.

While ISA-5.1 deals with instrumentation and control content on various engineering drawings, including PFDs and P&IDs, this new TR will provide guidance and examples specific to PFDs and P&IDs.