A roulette wheel? An AC Milan kit? Darth Maul's face?

Question

I've just been summoned to my Professor's office. A few minutes ago I knocked on his door, and after his familiar cry of "Come in, sport," I sat with him at his table and we talked about the upcoming paper we were co-writing about pattern-spotting. During the discussion, I couldn't help but notice a new artwork in a frame on the wall behind his desk.

"Ah, I see you're contemplating my latest acquisition," he said. "It's a mosaic, but unfortunately five of the tiles broke off."

"Oh, how did it break?" I asked out of courtesy.

"Actually rather well - couldn't have gone better!" he laughed, weirdly, so I did the polite thing and laughed too. Gah, why did I laugh - now I look like a sycophant...

"In fact, I have the missing five tiles in one of my pockets," he went on. "And you and I - we share certain interests; when it comes to pattern-spotting, we're cut from the same cloth, don't you think? So here's a challenge... If I tell you the missing tiles are not three reds and two blacks, can you tell me what colours they are? They do complete the pattern perfectly..."

I thought for a moment. "Hmmm... There's no silly semantics going on here, are there? The answer's not going to be something like 'they're not three reds and two blacks because they're actually two blacks and three reds,' right?"

"Absolutely - no tricks. There's a genuine pattern for you to find here. And if you can get it in one attempt, I'll even let you be first author on the paper - so hit me with your best shot..."

At this, I asked whether he might be able to give me a clue, but instead he gave me a wry look and questioned whether I'd been listening to him at all. I'm looking - I really am - but I'm not seeing anything other than the obvious (wrong) answer, and my Professor insists he's given me the most amount of help he's willing or able to give. I'm really in a very difficult position here - what's the solution??

What colours should replace the question marks to complete the Professor's pattern. Why? What hints did he drop that might help me work out what's going on here?

^{Text description of the grid, for accessibility (R=Red, B=Black, ?=Missing):}

RBRBRB
RBRBRB
RBRBRB
RBRBRB
RBRBRB
?????B

Answer 1

I believe the mosaic should look something like this:

because:

it depicts a maximum break in snooker, which involves scoring the balls in the exact order present- alternating red and black until all red balls have been potted, then scoring the other colors in ascending point order.

PSA for my clue explanations- I don't actually play or know all that much about snooker (I picked it up from the clues), so my apologies if my depictions are somewhat off or if I missed anything:

The clues he gave are:

1. "Come in, sport"- snooker is officially classified as a sport
2. "How did it break?" // "Actually very well, couldn't have gone better" - a "break" is another name for one player's turn- and this depicts the best possible one (this is what gave it away for me, plus some Googling to confirm the other terms & scoring pattern)
3. "one of my pockets"- snooker, like all cue games, requires a player to hit the ball into a pocket
4. "cut from the same cloth"- snooker is played on a cloth surface
5. "They do complete the pattern perfectly..." - another allusion to the fact that this is the best possible break
6. "hit me with your best shot"- typically a hit of the cue ball is called a "shot"