[Si-Co]

The latter was a thing that happened every so often - ISTR someone who worked in continuity at the time said that the colours could just be changed with a rotary knob - and they'd sometimes make it pink on valentines or whatever.

I seem to remember reading about an announcer who changed the colours to something “spooky” for a Hallowe’en promotion or similar, but was then unable to change them back and the globe or clock went out looking very odd!