"Giving the knee"

[Taunton Blue Genie]

The number of colours in a rainbow is an interesting subject:
https://www.languagesoftheworld.info...9;light%20blue').

And did you know that Japanese traffic lights are red, amber and......blue?
https://www.mentalfloss.com/article/...nfinitescroll1

And if any of you are interested in the nature of the perception of colour and the linguistics used to express it (and I am probably boring you all to death, as usual) a Namibian tribe has an interesting take on such things:
https://www.gondwana-collection.com/...as-see-colour/