How about this?

plots:-display([seq(plots:-matrixplot(Matrix(M[() .. (), () .. (), T]), axes = boxed, tickmarks = [[1 = "0", 2 = " ", 3 = " ", 4 = " ", 5 = ".4", 6 = " ", 7 = " 0.6", 8 = " ", 9 = ".8", 10 = " ", 11 = "1"], [1 = "0", 2 = " ", 3 = " ", 4 = " ", 5 = ".4", 6 = " ", 7 = " 0.6", 8 = " ", 9 = ".8", 10 = " ", 11 = "1"], default], labels = [x, y, u], axes = boxed), T = 1 .. 11)], insequence = true);