(A) Quasistatic average angle Θ as a function of d/D for glass beads, in comparison with the similar results in refs. [21, 11]. Inset shows the associated Δθ as a function of d/D. (B) θ_m versus θ_r for five types of beads of d = 5/6 mm (solid cubes). Also included are the data of small glass beads in (A) (empty cubes) as well as previous literature [13, 21, 31, 11]. Straight line indicates the linear fit (see text). (C) θ_m versus Δθ for the data in (B). Straight line in (B) is also transformed.