From top to bottom panels: projected Rayleigh statistic (V, Eq. (A.10)), its variance (σ_V, Eq. (A.11)), its variance estimated using the Monte Carlo sampling introduced in Sect. B.1, and r values from channel pairs with V > 3ς_V, where ς_V represents the population variance of V in the indicated velocity range, as estimated from Eq. (5). These values correspond to the relative orientation angles ϕ calculated between HI and ¹³CO velocity-channel maps in the range 30 < v_LSR <60 km s⁻¹.