Switchback

This design is related to the Latin Square Design. There are "rows" and "columns", both of which are blocking factors. However, the number of columns is usually equal to the number of unique pairs of treatments [equal to t*(t-1)/2], and the number of rows is generally only 3 or 4, not related to the number of treatments as in an LSD. The primary objective of the switchback design is to control for row and column differences, and additionally to control for the columns changing differently across the rows.

See also: What is a Switchback design?