A toy. Moving the left stick causes a circle to move, trailing same-coloured particles. Pressing X, A or B causes the colour to be said, turns the circle that colour and flashes that colour in the entire bg. Pressing Y makes rude noises. Bumpers do something unknown.
Really, this is the kind of thing that I'm only mentioning for the sake of completionism. But since I am: I certainly respect the idea of a 'game' that is more about getting to know the buttons than overcoming any extra challenges. However, I'm not sure that the 360's pad is something that is important enough to merit training a baby for. I think that I would rather give my actual niece or hypothetical future child a physical toy since learning about real physics seems more worthwhile. Or when she's old enough to benefit from computer games, maybe a physical rhythm-based game or a simple 2D platformer would be a better starting point.
I think that ultimately, I maybe just disagree with this dude in when children should be introduced to videogames (specially looking at the picture). I applaud the broadening of the medium though.
Saying 3 of the colours out loud could help them be learned.
It seems a bit arbitrary and generally unexciting for the right analogue stick, d-pad and the triggers to do nothing.
Lesson?: Not everyone thinks alike. Some people have totally different opinions. Maybe all opinions are justified.
(Alternative lesson): some things are better in our real environment rather than being turned into a computer game. Like childrens' toys - so many interactions are possible with 2 plastic bricks, let along 5 of varying sizes! Or like cycling.