Complex v Complicated

According to the dictionary:

complex adj. complicated.
complicated adj. complex.

which is no help.

Complex means to be made up of related parts. So something complex is going to be fiddly to deal with, it will probably lave lots of components. Something that needs care and attention to detail. Building a house out of Lego, with doors, windows, shutters, pot plants, roof tiles and making everything line up with no gaps is complex. But a small child could do it. There are only so many Lego blocks and they ony go together in particular ways. There's just a lot of it.

Complicated means intricate, difficult or confused. So something complicated will require specialist knowledge to understand it. The Lord of the Rings is complicated.

Complex is the opposite of simple. Complicated is the opposite of easy.

The driverless trains on the Docklands Light Railway are complex. Using them is not complicated.

Using a London Underground train is not complex. Working out how to cross London on public transport is complicated.

Woah! Hold it right there!

I have just gone through about 30 pages online and some say complex is A and complicated is B while others say complex is B and complicated is A. They even sometimes share the same examples for each, but the other way around. Is someone out there having a laugh? Or it might be a matter for linguistic analysis. Perhaps mathematics uses them as jargon terms one way and engineering uses them the other. Psychiatry has specific meanings for complex and complicated, as does architecture.

I suspect the terms complex and complicated are best avoided unless you are using them in a very particular context, such as the Cynefin framework, where definitions are provided.