On peut parler français, pas de problème. On a second thought, never mind, I don't know how to critique in french. So your assignment... right now Heads are very solid, I see you're trying to vary jaw shapes, very nice. There are some problems: Second head: you wouldn't see the outer cheek from this angle. I fell that you extended too much the chin. Third Head: Pay attention to the shape of the jaw. From this angle you might start to see a little bottom plane or at least the corners of the jaw would be lower. The other heads I think you're exaggerating the bottom third and you're drawing too much front plane. I'ts possible having wide faces and longer chins. But try really getting a grasp on the classic measures or in the future you may find it difficult drawing women for example. Good work, keep drawing, Best Regards