These first messages were sent in late 1971. The next release of TENEX went out in early 1972 and included the version of SNDMSG with network mail capabilities. The CPYNET protocol was soon replaced with a real file transfer protocol having specific mail handling features. Later, a number of more general mail protocols were developed.
Circle (Wikipedia)A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the centre. The distance between any point of the circle and the centre is called the radius.