diff --git a/src/run.jl b/src/run.jl
index f076b97..92ae2e7 100644
--- a/src/run.jl
+++ b/src/run.jl
@@ -1,12 +1,13 @@
 function run(;
     N::Int64,
     T::Float64,
-    v::Float64=20.0,
-    δt::Float64=2e-5,
+    v::Float64,
+    δt::Float64=1e-5,
     save_at::Float64=0.1,
     framerate::Int64=0,
     save_data::Bool=true,
-    n_steps_before_verlet_list_update::Int64=100,
+    n_steps_before_verlet_list_update::Int64=1000,
+    packing_ratio::Float64=0.5,
     debug::Bool=false,
 )
     Random.seed!(42)
@@ -23,7 +24,7 @@ function run(;
 
     N = grid_n^2
 
-    l = float(sqrt(N))
+    l = sqrt(N * π / packing_ratio) * σ / 4
     grid_box_width = 2 * l / grid_n
 
     skin_r = 1.1 * (2 * v * n_steps_before_verlet_list_update * δt + 2 * interaction_r)
@@ -60,8 +61,32 @@ function run(;
 
     save_variables_to_JSON = false
 
+    additional_variables = (;
+        T,
+        δt,
+        save_at,
+        framerate,
+        n_steps_before_verlet_list_update,
+        packing_ratio,
+        debug,
+        μ,
+        D₀,
+        particle_diameter,
+        Dᵣ,
+        σ,
+        ϵ,
+        interaction_r,
+        grid_n,
+        l,
+        grid_box_width,
+        skin_r,
+        integration_steps,
+        n_steps_before_save,
+        end_time,
+    )
+
     if save_data
-        save_data_jld(filename, sol, args, n_steps_before_verlet_list_update)
+        save_data_jld(filename, sol, args, additional_variables)
 
         save_variables_to_JSON = true
     end
@@ -73,7 +98,7 @@ function run(;
     end
 
     if save_variables_to_JSON
-        save_JSON(filename, args, n_steps_before_save)
+        save_JSON(filename, args, additional_variables)
     end
 
     return (; sol, args, filename)