This kid is trying SO HARD to move and crawl. You can tell he knows exactly where he wants to go and yet the only thing he knows how to do is spin in circles on his belly. (All of my Friends fans out there: cue Ross Geller yelling "PIVOT! PIVOT! PIVOT!)
He will go from content to angry in mere seconds when he can't propel himself closer to a toy or his brother. You have to give him credit though, he's not without trying, nor drool for that matter.