Figure 1.

Diagrammatic representation of four experimental layouts (X _lj; 1 ≤ l ≤ L, 1 ≤ j ≤ T). Light‐shading indicates X _lj = 0, dark‐shading indicates X _lj = 1. The values of the coefficients A and B depend only on the patterns of light and shade in these figures and not on the dimensions L and T. (a) Crossover; (b) Parallel; (c) SW₄; (d) DCD_{0.25, 0.5, 0.25}