using CairoMakie
f = Figure()
Axis(f[1, 1])
xs = LinRange(0, 6.3, 80)
ys = LinRange(0, 9.5, 80)
zs = [sin(x/2) * 0.5sin(y) for x in xs, y in ys]
contour!(zs,levels=-1:0.1:1)
f
using CairoMakie
f = Figure()
Axis(f[1, 1])
xs = LinRange(0, 6.3, 80)
ys = LinRange(0, 9.5, 80)
zs = [sin(x/2) * 0.5sin(y) for x in xs, y in ys]
contour!(zs,levels=-1:0.1:1)
f