Actions with purpose

Tobias loves to just sit and play. He can do that for long periods at a time. Of course now that he can crawl faster and faster he wants to do that too, but I love to watch him "investigate" his toys. Today I introduced a new toy for him, this lovely train. When you push the yellow thing, depicting a dog, it rides and plays a song and it whistles. Of course Tobias did not know that when I first gave it to him. After I showed it to him a couple of times he figured it out for himself and had to laugh and laugh, especially because not only does the train rides and plays a song and whistles, but also because in the exhaust pipe in the front there is an orange thing, depicting a cat, that goes up and down.... He loves that! I guess what I am trying to say is that Tobias is getting more and more purpose to his actions. He crawls towards something and then picks it up to play with it, he throws stuff on the floor counting on us to pick it up (that's so funny, right...?), and in this case he realizes (or at least seems to realize) that if he pushed the yellow thing something happens with the train (or maybe in his terms; the big blue thing.....)