diff --git a/demo/interactivity.jl b/demo/interactivity.jl
index 07e730b..421f301 100644
--- a/demo/interactivity.jl
+++ b/demo/interactivity.jl
@@ -22,5 +22,73 @@ interactive_raycurves(
     z_src = 0.0,
     num_rays = 5,
     min_angle = atan(5, 20),
-    max_angle = atan(5, 2)
+    max_angle = atan(5, 2),
 )
+
+##
+using OceanSonar, GLMakie
+
+cel = OceanCelerityProfile("Homogeneous")
+ati = AltimetryProfile("Flat")
+bty = BathymetryProfile("Parabolic")
+Rsrf = ReflectionCoefficientProfile("Reflective")
+Rbot = ReflectionCoefficientProfile("Mirror")
+
+r_max = 20e3
+z_src = 0.0
+num_rays = 5
+min_angle = atan(5, 20)
+max_angle = atan(5, 2)
+r_min = 0.0
+r_max = 20e3
+z_min = OceanSonar.IntervalArithmetic.interval(r_min, r_max) |> ati |> OceanSonar.IntervalArithmetic.inf
+z_max = OceanSonar.IntervalArithmetic.interval(r_min, r_max) |> bty |> OceanSonar.IntervalArithmetic.sup
+z_src = 0.0
+
+fig = Figure()
+
+axis = Axis(fig[1, 1],
+    yreversed = true
+)
+
+z₀s = [z_src; range(ati(r_min), bty(r_min), 5)] |> uniquesort! |> reverse
+
+depth_slider = Slider(fig[1, 0],
+    range = z₀s,
+    horizontal = false,
+    startvalue = z_src,
+    snap = true
+)
+
+θ₀s = range(min_angle, max_angle, num_rays)
+
+function fan2rays(z₀)
+    fan = Fan("Gaussian", θ₀s, z₀, r_max, 1e3, cel, bty, Rbot, ati, Rsrf)
+    beam2ray.(fan.beams)
+end
+
+function beam2ray(beam)
+    s = range(0, beam.s_max, 301)
+    r = beam.r(s)
+    z = beam.z(s)
+    Point2.(r, z)
+end
+
+rays = Dict(
+    z₀ => fan2rays(z₀) for z₀ in z₀s
+)
+
+curve = lift(depth_slider.value) do z₀
+    rays[z₀]
+end
+
+celerityheatmap!(axis, cel, r_min, r_max, z_min, z_max)
+altimetryband!(axis, ati, r_min, r_max)
+bathymetryband!(axis, bty, r_min, r_max)
+series!(axis, curve, solid_color = :black)
+
+limits!(axis, r_min, r_max, z_min, z_max)
+
+axis.yreversed = true
+
+fig