This creates "nasolabial folds, " lines that extend from the tip of the nose to the corners of the lips: the parentheses of the face.

The zygomatic major muscle that turns the corners of the lips up, and the orbicularis oculi muscle that squeezes the eyes into the famous fanned wrinkles otherwise known as crows feet.

It put forward a mechanical model to simulate the forehead wrinkles, crow's feet and wrinkles of corners of the mouth.