In general usage, symmetry most often refers to mirror or reflective symmetry; that is, a line (in 2-D) or plane (in 3-D) can be drawn through an object such that the two halves are mirror images of each other. Symmetry is a fundamental part of geometry, nature, and shapes. It creates patterns that help us organize our world conceptually. We see symmetry every day but often don't realize it. People use concepts of symmetry, including translations, rotations, reflections, and tessellations as part of their careers. An isosceles triangle and a human face are examples—a reflection of trees in clear water and reflection of mountains in a lake. Wings of most butterflies are identical on the left and right sides. Some human faces are the same on the left and right side. People can also have symmetrical moustache.