y = 1
z = 2
y = 1
z = 2
y = 1
z = 2

y = 3
z = 4
y = 3
z = 4
y = 3
z = 4

y = 5
z = 6
y = 5
z = 6
y = 5
z = 6

y = 7
z = 8
y = 7
z = 8
y = 7
z = 8

y = 9
z = 10
y = 9
z = 10
y = 9
z = 10

y = 11
z = 12
y = 11
z = 12
y = 11
z = 12