diff --git a/src/main.rs b/src/main.rs
index 492e1ca..3475f8a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -198,36 +198,38 @@ fn display_grid(
     w: &world::World,
     robot_pool: &Vec<robot::Robot>,
     h: &HashMap<robot::Position, u32>,
-) {
+) -> String {
+    let mut grid = String::new();
     for i in (0..w.y + 1).rev() {
         if i < 10 {
-            print!("{}  ", i);
+            grid = format!("{}{}  ", grid, i);
         } else {
-            print!("{} ", i);
+            grid = format!("{}{} ", grid, i);
         }
         for j in 0..w.x + 1 {
             match h.get(&robot::Position { x: j, y: i }) {
                 Some(id) => match robot_pool[(id - 1) as usize].o {
-                    robot::Orientation::N => print!("↑  "),
-                    robot::Orientation::E => print!("→  "),
-                    robot::Orientation::S => print!("↓  "),
-                    robot::Orientation::W => print!("←  "),
+                    robot::Orientation::N => grid = format!("{}↑  ", grid),
+                    robot::Orientation::E => grid = format!("{}→  ", grid),
+                    robot::Orientation::S => grid = format!("{}↓  ", grid),
+                    robot::Orientation::W => grid = format!("{}←  ", grid),
                 },
 
-                None => print!(".  "),
+                None => grid = format!("{}.  ", grid),
             }
         }
-        println!();
+        grid = format!("{}\n", grid);
     }
-    print!("   ");
+    grid = format!("{}   ", grid);
     for j in 0..w.x + 1 {
         if j < 10 {
-            print!("{}  ", j);
+            grid = format!("{}{}  ", grid, j);
         } else {
-            print!("{} ", j);
+            grid = format!("{}{} ", grid, j);
         }
     }
-    println!();
+    grid = format!("{}\n", grid);
+    grid
 }
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
@@ -262,11 +264,13 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     let mut hash: HashMap<robot::Position, u32> = HashMap::new();
     create_hash_map(&robot_pool, &mut hash);
-    println!("World {{ x_max = {}; y_max = {} }}", world.x, world.y);
-    robot::print_robots(&robot_pool);
-    println!("Initial state");
-    println!("==============");
-    display_grid(&world, &robot_pool, &hash);
+    let mut print_all = format!("World {{ x_max = {}; y_max = {} }}\n", world.x, world.y);
+    print_all = format!("{}{}", print_all, robot::print_robots(&robot_pool));
+    if world.x <= 60 && world.y <= 45 {
+        print_all = format!("{}Initial state\n", print_all);
+        print_all = format!("{}==============\n", print_all);
+        print_all = format!("{}{}", print_all, display_grid(&world, &robot_pool, &hash));
+    }
     loop {
         let mut piouff: u32 = 0;
         for r in &mut robot_pool {
@@ -280,13 +284,22 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
                 hash.insert(robot::Position { x: r.p.x, y: r.p.y }, r.id);
             }
         }
+        if world.x <= 60 && world.y <= 45 {
+            std::thread::sleep(std::time::Duration::from_millis(600));
+            print!("\x1B[2J\x1B[1;1H");
+            print!("{}", display_grid(&world, &robot_pool, &hash));
+        }
         if piouff == robot_pool.len() as u32 {
             break;
         }
     }
-    println!("Final state");
-    println!("============");
-    display_grid(&world, &robot_pool, &hash);
+    print!("\x1B[2J\x1B[1;1H");
+    print!("{}", print_all);
+    if world.x <= 60 && world.y <= 45 {
+        println!("Final state");
+        println!("============");
+        print!("{}", display_grid(&world, &robot_pool, &hash));
+    }
     for r in &robot_pool {
         println!("Robot id: {}: Final position: ({}, {})", r.id, r.p.x, r.p.y);
     }
diff --git a/src/robot.rs b/src/robot.rs
index 932fa85..2856d46 100644
--- a/src/robot.rs
+++ b/src/robot.rs
@@ -95,11 +95,12 @@ pub fn is_piouff(r: &Robot) -> bool {
 }
 
 /// Print robots id, position and instructions.
-pub fn print_robots(robot_pool: &Vec<Robot>) {
-    println!("Robots [");
+pub fn print_robots(robot_pool: &Vec<Robot>) -> String {
+    let mut res = format!("Robots [\n");
     for r in robot_pool {
-        println!(
-            "{{ id = {}, x = {}; y = {}; orientation: {}, instructions: {:?}, }},",
+        res = format!(
+            "{}{{ id = {}, x = {}; y = {}; orientation: {}, instructions: {:?}, }},\n",
+            res,
             r.id,
             r.p.x,
             r.p.y,
@@ -112,7 +113,8 @@ pub fn print_robots(robot_pool: &Vec<Robot>) {
             r.i
         );
     }
-    println!("]");
+    res = format!("{}]\n", res);
+    res
 }
 
 #[cfg(test)]
diff --git a/src/world.rs b/src/world.rs
index 5ad774f..7f3f4c1 100644
--- a/src/world.rs
+++ b/src/world.rs
@@ -9,7 +9,7 @@ pub struct World {
 /// Create a random World.
 pub fn random_world() -> World {
     let mut rng = rand::thread_rng();
-    let z = rng.gen_range(5, 50);
+    let z = rng.gen_range(5, 45);
     World { x: z, y: z }
 }