x = [1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4];
y = [1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4];
z = [1 2 3 4 2 3 4 5 5 6 7 8 9 10 11 12];
e = rand(16,1)*2;