diff --git a/simulations/mouvement_brownien.R b/simulations/mouvement_brownien.R
index 2fe6729..9e15831 100644
--- a/simulations/mouvement_brownien.R
+++ b/simulations/mouvement_brownien.R
@@ -4,9 +4,9 @@ library(ggplot2)
 N <- 1000
 time_delta <- 0.5
 
-generate_brownian_movement_traj <- function(N, time_delta) {
+generate_brownian_motion_traj <- function(N, time_delta, variance = 1) {
     # BM indep vector
-    bm_indep <- rnorm(N, mean = 0, time_delta)
+    bm_indep <- rnorm(N, mean = 0, sqrt(time_delta * variance))
 
     # The trajectory
     bm_traj <- cumsum(bm_indep)
@@ -15,9 +15,13 @@ generate_brownian_movement_traj <- function(N, time_delta) {
     return(data.frame(time_serie = time_serie, bm_traj = bm_traj))
 }
 
-bm_traj_and_time <- generate_brownian_movement_traj(N, time_delta)
+bm_traj_and_time <- generate_brownian_motion_traj(N, time_delta)
 
-# Plotting
-ggplot(bm_traj_and_time) +
-    aes(x = time_serie, y = bm_traj) +
-    geom_line()
+# Generate multiple BM
+
+
+# For phylogenic tree
+
+generate_phylo_tree <- function(n_tips, max_time) {
+
+}
\ No newline at end of file