diff --git a/scripts/run_simulation.jl b/scripts/run_simulation.jl
index bb923e3..6eb584e 100644
--- a/scripts/run_simulation.jl
+++ b/scripts/run_simulation.jl
@@ -1,31 +1,131 @@
-include("../src/AnimalFurFHN.jl")  # this loads the module code
+using GLMakie, Observables
 using .AnimalFurFHN
-# include optional visualizer only if needed:
-include("../src/visualization.jl")
-using .Visualization
-
-N = 256
-# tspan = (0.0, 1000.0)
-
-# sol = AnimalFurFHN.run_simulation(tspan, N)
 
 
-# Visualization.step_through_solution(sol, N)
+# Parameters and initial conditions
+N = 128
+dx = 1.0
+Du, Dv = Observable(0.16), Observable(0.08)
+F, k = Observable(0.060), Observable(0.062)
+dt = 1.0
+params_obs = Observable(AnimalFurFHN.GSParams(N, dx, 0.16, 0.08, 0.08, 0.06))
 
-using Plots
-
-function animate_gray_scott(sol, N; var=:U)
-    anim = @animate for t in 1:length(sol.t)
-        u = reshape(sol[t][1:N^2], N, N)
-        v = reshape(sol[t][N^2+1:end], N, N)
-        data = var == :U ? u : v
-        Plots.heatmap(data, c=:magma, title="$var at t=$(Int(sol.t[t]))", clims=(0, 1))
-    end
-    gif(anim, "gif/gray_scott.gif", fps=15)
+function update_params!(params_obs, u, v, feed, kill)
+    old = params_obs[]
+    params_obs[] = AnimalFurFHN.GSParams(old.N, old.dx, u, v, feed, kill)
 end
 
-# set time to more than 1000
-sol = AnimalFurFHN.run_simulationG((0.0, 10000.0), 256)
+lift(Du, Dv, F, k) do u, v, F, k
+    update_params!(params_obs, u, v, F, k)
+end
+U = ones(N, N)
+V = zeros(N, N)
+center = N ÷ 2
+radius = 10
+U[center-radius:center+radius, center-radius:center+radius] .= 0.50
+V[center-radius:center+radius, center-radius:center+radius] .= 0.25
 
-Visualization.step_through_solution(sol, N)
-# animate_gray_scott(sol, 256, var=:U)
+# Observable holding current U for heatmap
+heat_obs = Observable(U)
+
+function laplacian5(f)
+    h2 = dx^2
+    left = f[2:end-1, 1:end-2]
+    right = f[2:end-1, 3:end]
+    down = f[3:end, 2:end-1]
+    up = f[1:end-2, 2:end-1]
+    center = f[2:end-1, 2:end-1]
+    return (left .+ right .+ down .+ up .- 4 .* center) ./ h2
+end
+
+function step!(U, V)
+    lap_u = laplacian5(U)
+    lap_v = laplacian5(V)
+
+    u = U[2:end-1, 2:end-1]
+    v = V[2:end-1, 2:end-1]
+
+    uvv = u .* v .* v
+    u_new = u .+ (Du[] .* lap_u .- uvv .+ F[] .* (1 .- u)) .* dt
+    v_new = v .+ (Dv[] .* lap_v .+ uvv .- (F[] .+ k[]) .* v) .* dt
+
+    # Update with new values
+    U[2:end-1, 2:end-1] .= u_new
+    V[2:end-1, 2:end-1] .= v_new
+
+    # Periodic boundary conditions
+    U[1, :] .= U[end-1, :]
+    U[end, :] .= U[2, :]
+    U[:, 1] .= U[:, end-1]
+    U[:, end] .= U[:, 2]
+
+    V[1, :] .= V[end-1, :]
+    V[end, :] .= V[2, :]
+    V[:, 1] .= V[:, end-1]
+    V[:, end] .= V[:, 2]
+
+    # Update heatmap observable
+    heat_obs[] = copy(U)
+end
+function multi_step!(state, n_steps)
+    for _ in 1:n_steps
+        step!(state[1], state[2])
+    end
+end
+
+# Build GUI
+fig = Figure(size=(600, 600))
+ax = Axis(fig[1, 1])
+
+
+
+hm = Makie.heatmap!(ax, heat_obs, colormap=:magma)
+ax.aspect = DataAspect()
+
+# # Controls
+
+fig[2, 1] = buttongrid = GridLayout(tellwidth=false)
+btn_step = Button(buttongrid[1, 1], label="Step")
+btn_start = Button(buttongrid[1, 2], label="Start")
+btn_stop = Button(buttongrid[1, 3], label="Stop")
+
+
+fig[3, 1] = textboxgrid = GridLayout(tellwidth=false)
+box_u = Textbox(textboxgrid[1, 1], validator=Float64, placeholder="word")
+# box_v = Textbox(textboxgrid[1, 2], validator=Float64, placeholder="word")
+# box_feed = Textbox(textboxgrid[1, 3], validator=Float64, placeholder="word")
+# box_kill = Textbox(textboxgrid[1, 4], validator=Float64, placeholder="word")
+# Timer and state for animation
+running = Observable(false)
+
+function animation_loop()
+    while running[]
+        # step!(U, V)
+        multi_step!((U, V), 30)
+        sleep(0.05)  # ~20 FPS
+    end
+end
+on(box_u.stored_string) do s
+    try
+        Du[] = parse(Float64, s)
+    catch
+        @warn "Invalid input for Du: $s"
+    end
+end
+
+on(btn_step.clicks) do _
+    multi_step!((U, V), 30)
+end
+
+on(btn_start.clicks) do _
+    if !running[]
+        running[] = true
+        @async animation_loop()
+    end
+end
+
+on(btn_stop.clicks) do _
+    running[] = false
+end
+
+display(fig)