English: A rotating vector, labeled "A" is tracing out a sin() function. A green "chain" is used to move the pen horizontally for tracing out the function. A black arc shows the angle changing as the tracing moves forward. The physical horizontal dimensions are strictly in radians as demonstrated by the "chain". However, all angles are notated in degrees. The rotation continues for 4 cycles before the animation repeats 4 times, for a total of 16 cycles, after which the animation stops. As the vector rotates, the degrees add up to more than 360 degrees to demonstrate the periodic nature of the sine function.