Numerous variations of the T formation have been developed, including the Power-T, where two tight ends are used, the Pro T, which uses one tight end and one wide receiver, or the Wing T, where one of the running backs (or wingback) lines up one step behind and to the side of the tight end. Any of these can be run using the original spacing, which produced a front of about seven yards, or the Split-T spacing, where the linemen were farther apart and the total length of the line was about fourteen yards.