Simultaneous populations of angles by Chol molecules rotating about their long axis (α) and relative to the normal (θ) during 100 ns sampled with a 1 ps time step for two representative Chol molecules in the POPC-Chol50 (a, b) and Chol-2 bilayers (c, d). The fastest rotating molecules about the long axis are represented in (a, c), and the slowest rotating molecules in (b, d). The angles α and θ are defined in the text. The color scale on the right-hand side codes logarithm of the number of cases when a given angle was populated during the analysis time. The white color indicates zero cases.