English: Products of two versors (Spin(3) elements) in both orders acting on a 2-sphere shown in w:stereographic projection. The versor f induces a 180° rotation (violet), but is represented with a 90° great arc (π/2 length, black). Such versors are termed right versors. The versor g induces a 60° rotation (yellow), but is represented with a 30° great arc (π/6 length, shown as two straight upwards black arrows). Two products of versors form two spherical triangles (green fill). Note that direction of 180° arrows is important: reversing them would result in same SO(3) elements, but in opposite versors represented with 90° great arcs in opposite direction (clockwise). The rotation of the g f product is shown in red, of f g is shown in azure; one can follow some compositions of violet and yellow arrows in different orders. Note that the right yellow circle has arrows spaced by 30° (one g rotation corresponds to two intervals between arrows). At the upper left corner there is a depiction of the same sphere in orthographic projection and a schema of the stereographic projection is present. Near side of the sphere corresponds to the lower side of the image and is seen upside-down (the main image shows the sphere from inside, whereas the orthographic projection shows its exterior view).