How many jokes are there below? One or two? Please help me understand it or them. Thanks a lot!

Spitfire

What's black and white, black and brown, and black and black?
A nun roasting on a spit.
It's one joke, and not a very nice one.

A spit is a device for cooking meat on a fire. Nuns wear black and white clothes. Can you work it out now?
Nona The BritIt's one joke, and not a very nice one.

A spit is a device for cooking meat on a fire. Nuns wear black and white clothes. Can you work it out now?

More reminders or just tell me the point, please? Thanks.
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It's an unpleasant joke. I'd rather not. Replace each comma with the word 'then' to work it out.
I understand the first sentence means the nun's clothes is getting burned. The second means the nun is cooking meat on a fire. Anyway, I do not get it.

Nona, you said this is an unpleasant joke, if you would not like to explain it here, would it be possible to tell me by email? Thanks a lot!
Nona The BritIt's an unpleasant joke. I'd rather not. Replace each comma with the word 'then' to work it out.
Osee, it means a PERSON is being cooked. Don't you think that's unpleasant?
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Osee, the nun isn't cooking meat, she is herself being cooked on the fire.
I think it has double meaning, like a num with a monk,you know, it isn't correct them both go to hell, or both burn in fire them both became black. Gotcha???

There is something funny in that, isn't it?
No, there's really no double meaning. It's just a rather nasty joke about someone being cooked on a spit. I would advise against telling it to anyone over the age of 13, if you feel you must tell it at all. I find NOTHING funny in it.
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