Que significa "sudar la gota gorda" ayudenme

Which principle of design is in primary use in this sculpture?

Im giving free points and brainiest to whoever gets here first lol

Acurious child asked his mother: “mommy, why are some of your hairs turning grey? ” the mother tried to use this occasion to teach her child: “it is because of you, dear. every bad action of yours will turn one of my hairs grey! ” the child replied innocently: “now i know why grandmother has only grey hairs on her head.”