Parallelogram Method

When two arrows or vectors (representing motions if you wish) have a tail at the same place, they may be added together by moving the tail of one to the head of the other with the aid of a parallelogram, and then using the head to tail method for addition. This gives the parallelogram method for adding a pair of arrows or vector addition. The resultant arrow does not depend on which arrow, the first or second, is moved. Here is a repeatable and reproducible methods, arbitrarily defined, for vector or arrow addition. More generally, parallelograms can be used to displace or move arrows from one location to another without changing their lengths or directions.