0 -> x x -> 0 x -> y_0 x -> L y_0 -> 0 y_0 -> y_1 L -> y_0 y_0 -> 0 y_1 -> 0 y_1 -> 0 L -> 0 0 -> v v -> 0 0 -> z_a 0 -> z_a z_a -> 0 m_0 -> 2*m_1 m_1 -> 2*m_2 m_2 -> 2*m_3 m_3 -> 2*m_4 m_4 -> 2*m_5 m_5 -> 2*m_6 m_6 -> 2*m_7 m_7 -> 2*m_8 m_8 -> 0 0 -> z_i 0 -> z_i z_i -> 0 y_0 -> 0 y_1 -> 0