You may see a student sleeping in class. I see an intricate set of independent actions working in concert to aid a student in her effort to sleep in class while giving the illusion of attention. The right arm has been raised a few inches by a stack of textbooks, thus lifting her right shoulder. As the left hand pushes her head to the right, the right shoulder is there to act as both a pillow for comfort and a kickstand to prevent her head from toppling onto the desk with an embarrassing thud. Her legs are apart, equally distributing her dead weight to keep her from falling. If her torso was leaned further forward, her legs would be crossed and tucked back beneath the seat to counterbalance the intensity of her slouch.
The technique of a future Hall of Famer.
But of course, the entire illusion would be rendered useless if not for her immaculate positioning behind another student. The girl in yellow has just enough slouch to be ducked behind the girl in red far enough to become an outline of an attentive teen when seen from the teacher's point of view. As long as the girl in yellow doesn't snore or have a dream where she's falling and suddenly jolt awake in an embarrassing panic, by the end of class she'll have cultivated enough energy to walk to her next class so she can fall asleep there, too.
The foundation of many slacker techniques stems from seat positioning, so all the best slackers always know how to ...