Hi all,

it is more than 2 curves problem now, I want to fill an area / region between 3 curves.

Currently I can only manage to fill area between 2 curves:

```
using Plots, LaTeXStrings, Roots, SymPy
gr()
x = collect(range(-4, 2, length= 100))
f1(x) = x + 6
f2(x) = x^3
f3(x) = -x/2
plot(f1,-5,5, xtick=-5:5:5, xlims=(-5,5), ylims=(-10,10),
framestyle=:zerolines,
label=L"y = x + 6", legend=:topleft)
plot!(f2,-5,5, xtick=-5:5:5, xlims=(-5,5), ylims=(-10,10),
framestyle=:zerolines,
label=L"y = x^{3}", legend=:topleft)
plot!(f3,-5,5, xtick=-5:5:5, xlims=(-5,5), ylims=(-10,10),
framestyle=:zerolines,
label=L"2y + x = 0", legend=:topleft)
plot!(x, f1, fillrange = f3, fillalpha = 0.35, c = 1,
label ="", legend=:topleft)
```