Obviously this is a game with a finite number of moves, so everything is a "pattern". Without ever playing the game, you could map out every possible move and every possible combination and fit whatever random sequence of moves one performed into one of your "pattern" templates. That being said, it's totally different for someone to beat a computer character with an actual "pattern", as in performing the same move, or the same sequence of moves, over and over again to exploit a weakness in code, then for a player to beat the computer with the exact same play style they use vs human opponents. If you cannot understand the distinction between these two scenarios I fear nobody can explain it to you.
There isn't much of a difference. The AI reads your reactions during your gameplay, if you play a certain style throughout the arcade ladder the AI will adapt to it.
For instance:
Round 1 on any AL will be an AI that hardly moves [although on the hardest difficulty they aren't just sitting ducks they help assess the next AIs you face further up on the ladder]
So if you play a certain style you will create a pattern within the AI previous to fighting them.
One match I kept abusing Scorpion's Telepunch/Spear. The next round I didn't use it but once. The AI instantly reacted to it which shouldn't happen in that round due to the fact that I threw it out at a completely random time. However, it had recorded information [like Psycho Mantis from MGS] who records information as you play through, not just from facing that match.
So if you play the same style throughout the entire arcade ladder you will set a ladder. The only difference is humans can adapt to AI patterns unlike the AI being able to adapt to us. However, if an AI is allowed off its pattern leash [Slightly seen in SC3/UMK3 which is known as "going crazy." ]The AI can pretty much defeat any attempt at winning. Because outside of patterns AI are impossible to beat. Similar to the super computer that beat the best chess player in the world. It was off its leash thanks to being allowed to calculate whatever it wanted.
Same as what I'm saying here. You may have no intentionally created a pattern, but you created one which means it can be defeated due to adaptation.
Example: You don't use throws and the AI starts blocking, BOOm, you've caused the AI to fall victim to them. (Though if you keep doing it they will form a pattern to prevent being thrown)
Edit: Yes I said they don't adapt, and I said they adapt.
To clarify, they adapt a pattern to your moves, but they can't adapt their own solution to your moves.