Search Results: what types of flirting is there

So, I have a crush on a guy that is in one of my classes in college. He is a grade older than me and tends to be the "joker" of the class. He will constantly try to make the professor laugh with "stupid" answers and in total make the whole class laugh. He isn't stupid or anything, he just likes that type of attention. So, I started "liking" him when we had to be put into groups for an essay peer review. It wasn't just me and him though, it was me, a girl, him, and another guy. So, the entire time he barely talked to me, and just talked (flirted) with the girl and the guy. He was basically ignoring me for no reason even though I barely knew him and never even talked to him. While he was talking with the girl (who sits next to me), he seemed nervous (he was fidgety and looked uncomfortable). My first thought was that he was nervous around the girl he was talking to, but if he was nervous around her, why would ignore me completely? I thought he was attractive before this incident but this situation made me a little confused.
So other than that incident, he never really seemed SUPER into me or was showing me all the signs. There have been a couple of times where we locked eyes with each other for a few seconds. When we do look at each other, he never looks away nervously (like a shy guy). He often keeps the eye contact. In class he does sit diagonally from me so, he often tries to position himself closer to me. He barely talks to me in class (ignores me) and he sometimes just asks the girl next to me random questions like "what was the homework?" or "did he grade that test?" There have been times where I could see him glance at me while looking in my direction. Outside of class, I barely see him or talk to him (bad sign probably lol). He does this weird thing where the minute that the professor says bye to us, he runs out the door.