(3-3)    Here are three snapshots from the experiment. 

Rock A is thrown by you (the pink one in the animation) and rock B is thrown by Nefertiti (the green one in the animation).

(a) shows the instant where the rocks are thrown

(b) is when they have their grazing collision

(c) is some time after the collision, where each rock has now been deflected and is moving slightly away from the line in the sand.