Answer:
A form of blocking by three variables.
Step-by-step explanation:
Graeco-Latin square design is a special type of comparative design.
Graeco-Latin square design uses 3 blocking variables unlike the 2 blocking variable as used by the standard Latin square design.
In this square design of experiment, the experimental units are grouped into three different ways.
maybe they are about to visit you or kill you or maybe something else
k = +4