The thing is, this isn't that difficult of a task. The disadvantage adults have in a task like this is, I believe without scientific evidence, the learned helplessness that so many adults have, probably induced from years of "education". A three year old flips through an iPad interface because nobody even thought to tell them it was hard; an adult that can't pick that up probably can't pick it up because they believe they can't pick it up.
In this case, there's 16 whole patterns to learn, and the patterns themselves are highly patterned so it's even easier than that. It's well within what a very young child can do. It's far easier than walking or speaking in sentences, those tasks that many two years olds already do better than our best AIs. (Yes, 2/3 year olds have characteristic grammar failures typical to the age... but then again, our best general-purpose AIs still botch things up too...)
Whether it's a faked video or not, I don't know or care... I see no reason to believe that a certain set of 2 years olds could do this, that a much larger set of 3 year olds could do this, and the vast majority of 4 year olds could do this, as long as they can concentrate for long enough. Indeed I would expect them to find this a boring task relatively quickly, because it's not that challenging.