Error in Fig 8.2

[lhupe]

Figure 8.2b shows the boundary map of a mushroom billiard, with a chaotic and two regular trajectories and the regular island shaded in gray. However, the shaded area seems to be too small: one of the regular trajectories (the teal one) is outside the regular island in the cap. Looking at the dimensions of this mushroom, the sin(θ) of the chaotic band in the cap should be within ±0.1 (the critical angle is sin(θ_c) = w/2R).

This error can't be reproduced with the corresponding script in this repo (8.3.jl) since the shading seems to be a later addition.