When things "click"

So I have been using the clicker to teach Cain how to indicate articles. We started by clicking when he looked at the article. Soon he would run to the article and come back for his treat. The next step was to get him to lay down and look at the article. So I started out by telling him to platz (down) when he ran to the article. To my surprise he did, this isn't exactly a solid command yet. So today we were working on this. Suddenly Cain got frustrated and started barking, jumping, biting at me and downing, but not by the article. This was actually good, he was offering behaviors (even if they weren't the right ones). Then he downed on the article, I clicked and treated. I moved the article, he leaped up and downed again on the article. Hooray!!!!! The behavior "clicked". He gets it and is soooooo excited about it! Next step is to put the article at the end of our track, but I am going to make sure the downing on the article is solid in multiple locations first, so maybe next week.