Still, at this point, when I introduce him to a lot of games, the pieces are just toys to him. Games are just a category of toys to him. (Wait a second! Games really are just a category of toys! He's further along than I thought!)
With that in mind, the way that he plays with them as toys can be close to how they are played as games. Katamino, which is basically a set of three-dimensional pentaminos, has long been something I've let him play with. However, in the last couple months, he has started to try and fit them on the wooden board like a puzzle, which is literally one of the ways to play Katamino. (Seriously, it's a great game if you like puzzling things out)
Also, with a heavy heart full of fear, I let him at Blokus Trigon, which is my favorite version of the game (I've gotten rid of the original version awhile ago) After he realized that the pieces will fit into the slots on the board, he began trying to fill the board with the pieces, which is the solitaire variant of the game. I'm now thinking of getting him a used copy of the original game to mess around with.
It is interesting watching him play with different kinds of games. Quite frankly, with all the different games that you can play with Looney Pyramids, I wouldn't be surprised if he's actually played some by accident. And watching him play with Piece Pack has made me wonder if I could make a version of That's Life with the pieces. Of course, I don't need to since I own it but it was an interesting thought exercise.