Example of a particle’s motion in its orbital plane (a special case of a closed orbit where Δφ = 3π/2) with the isochrone parameters μ = 1 and b = 2 × 10⁻¹. The green and blue circles, labelled C_rp and C_ra, respectively show the particle’s minimum and maximum radial positions. The dashed violet line, denoted by r(t), shows the particle’s orbit. The solid violet line shows the path of the particle during one radial period; its length is given by Γ (see Eq. (A.4)). The small arrow indicates the rotational sense of the loops.