quiver

using ImageFiltering

using AbstractPlotting

x = range(-2, stop = 2, length = 21)
y = x
z = x .* exp.(-x .^ 2 .- (y') .^ 2)
scene = contour(x, y, z, levels = 10, linewidth = 3)
u, v = ImageFiltering.imgradients(z, KernelFactors.ando3)
arrows!(x, y, u, v, arrowsize = 0.05)