{
w = 0.5 (0.5 (4 + 0.8 x) + 0.5 (2 + 0.8 y)) + 0.5 (3 + 0.8 z),
x = 0.5 (0.8 (0.8 z) + 0.2 (25 + 0.8 z)) + 0.5 (0.8 z),
y = 0.5 (1 + 0.8 z) + 0.5 (5 + 0.8 z),
z = 0.5 (0.8 z) + 0.5 (0.8 z)
}