Here is a chart depicting the gaits between trot (diagonal) and pace (lateral). The running walk is a square gait, as well as the flat walk and the walk. To the diagonal is the fox trot and fox walk. To the lateral is the rack (tolt) and stepping pace.



The running walk is a square gait as it is even in pick up and even in set down. The rack (tolt) is a lateral gait as it is lateral in pick up and even in set down.

For further descriptions of the easy gaits, see Lee Ziegler's Article on Identifying the Symmetrical Gaits of Horses.