using AbstractPlotting struct FitzhughNagumo{T} ϵ::T s::T γ::T β::T end P = FitzhughNagumo(0.1, 0.0, 1.5, 0.8) f(x, P::FitzhughNagumo) = Point3f0( (x[1]-x[2]-x[1]^3+P.s)/P.ϵ, P.γ*x[2]-x[2] + P.β, P.γ*x[1]-x[3] - P.β, ) f(x) = f(x, P) streamplot(f, -1.5..1.5, -1.5..1.5, -1.5..1.5, colormap = :magma, gridsize = (10, 10), arrow_size = 0.06)