diff --git a/argparser.c b/argparser.c
index d56a555..9619fd3 100644
--- a/argparser.c
+++ b/argparser.c
@@ -3,7 +3,7 @@
 #include "argparser.h"
 
 void usage() {
-	printf("Cosmology: -c <param file> [--debug]\n");
+	printf("Astrophysics: <option> <param file> [--debug]\n");
 }
 
 int getArgs(char *arg) {
@@ -11,7 +11,7 @@ int getArgs(char *arg) {
 	int i;
 	/* List arguments */
 	char listArgs[3][BUF_SIZE];
-	strcpy(listArgs[0], "-c"); // Gravity
+	strcpy(listArgs[0], "-p"); // Projectile
 
 	for(i = 0; i < 3; i++){
 		if(strcmp(listArgs[i], arg) == 0)
diff --git a/main b/main
index afdcb7f..8d0589a 100755
Binary files a/main and b/main differ
diff --git a/main.c b/main.c
index 5167d3a..c94a7f0 100644
--- a/main.c
+++ b/main.c
@@ -63,7 +63,7 @@ int main(int argc, char *argv[]) {
 	mainInitProjectile(yamlFile, &s_projectile, s_planet1.grav);
 
 	switch (argv[1][1]){
-		case 'c':
+		case 'p':
 			handleProjectile(&s_projectile, &s_planet1, debug);
 			break;
 		default:
@@ -113,8 +113,8 @@ static void mainInitProjectile(const struct yamlFile *yamlFile, struct projectil
 	s_projectile->masse = parseYamlFileInt(yamlFile, "Projectile:masse");
 	s_projectile->alpha = parseYamlFileDouble(yamlFile, "Projectile:angle");
 	deg_to_rad = degree_to_radian(s_projectile->alpha);
-	s_projectile->v0x = calcul_initial_speed(deg_to_rad, v0, 'x');
-	s_projectile->v0y = calcul_initial_speed(deg_to_rad, v0, 'y');
+	s_projectile->v0x = calculate_initial_speed(deg_to_rad, v0, 'x');
+	s_projectile->v0y = calculate_initial_speed(deg_to_rad, v0, 'y');
 	s_projectile->rect.x = s_projectile->x;
 	s_projectile->rect.y = s_projectile->y;
 	s_projectile->rect.w = s_projectile->height;
@@ -122,11 +122,11 @@ static void mainInitProjectile(const struct yamlFile *yamlFile, struct projectil
 
 	/***** Informations about the projectile *****/
 	// Calcul delta t
-	s_projectile->deltat = calcul_delta_t(s_projectile->v0y, grav);
+	s_projectile->deltat = calculate_delta_t(s_projectile->v0y, grav);
 
 	// calcul distance in meter
-	s_projectile->distance = calcul_distance_total(s_projectile->v0x, s_projectile->deltat);
+	s_projectile->distance = calculate_total_distance(s_projectile->v0x, s_projectile->deltat);
 
 	// Calcul height Max
-	s_projectile->hmax = calcul_height_max(0.0, s_projectile->v0y, grav);
+	s_projectile->hmax = calculate_height_max(0.0, s_projectile->v0y, grav);
 }
diff --git a/motion.c b/motion.c
index 8aa7ec0..7883791 100644
--- a/motion.c
+++ b/motion.c
@@ -1,35 +1,47 @@
 #include "motion.h"
 #include <math.h>
 
-double calcul_initial_speed(double alpha, double speed, const char c) {
-  // We calculated the v0 of y
+/*
+ * Here, we calculate the initial speed
+ * Where alpha is the initial launch angle
+ * speed is the initial speed
+ * and c defined if we calculate for x or y
+ */
+double calculate_initial_speed(double alpha, double speed, const char c) {
+  // We calculated the v0 of x
   if (c == 'x')
     return speed * cos(alpha);
-  // Otherwise, we calculated the v0 of x
+  // Otherwise, we calculated the v0 of y
   else
     return speed * sin(alpha);
 }
 /*
- * This function calcul the during of the time before the projectile have touche the ground
+ * This function calcul the during of the time before the projectile have reach the ground
+ * Where v is the initial speed of xor y
+ * and grav is the gravitational force
  */
- double calcul_delta_t(double v, double grav){
+ double calculate_delta_t(double v, double grav){
    return (2 * v) / grav;
  }
 /*
  * This function calcul the distance total of the projectile
+ * Where v is the initial speed of Vx
+ * and deltat is the result total time of flight
  */
- double calcul_distance_total(double v, double deltat){
+ double calculate_total_distance(double v, double deltat){
    return v * deltat;
  }
  /*
   * This function calcul the height max of the Projectile
+  * Where vx and xy are the initial speeds
+  * and grav is the gravitational force
   */
-  double calcul_height_max(double vx, double vy, double grav){
+double calculate_height_max(double vx, double vy, double grav){
     return (pow(vx, 2) - pow(vy, 2)) / (2 * -grav);
-  }
+}
 /*
  * This function convert the degree in radian
  */
- double degree_to_radian(double degree){
-   return degree * M_PI / 180;
- }
+double degree_to_radian(double degree){
+  return degree * M_PI / 180;
+}
diff --git a/motion.h b/motion.h
index b99ac0e..ecddd3c 100644
--- a/motion.h
+++ b/motion.h
@@ -1,10 +1,10 @@
 #ifndef H_MOTION
 #define H_MOTION
 
-double calcul_initial_speed(double, double, const char);
-double calcul_delta_t(double, double);
-double calcul_distance_total(double, double);
-double calcul_height_max(double, double, double);
+double calculate_initial_speed(double, double, const char);
+double calculate_delta_t(double, double);
+double calculate_total_distance(double, double);
+double calculate_height_max(double, double, double);
 double degree_to_radian(double);
 
 #endif
diff --git a/sdl/projectile.c b/sdl/projectile.c
index 5ab20ad..a4420e8 100644
--- a/sdl/projectile.c
+++ b/sdl/projectile.c
@@ -5,7 +5,7 @@
 #include "projectile.h"
 
 /* State of projectile */
-int isLaunch;
+static int isLaunch;
 
 /*
  * This function initialize our Projectile
@@ -174,7 +174,7 @@ void handleProjectile(struct projectile *s_projectile, const struct object *s_pl
 	args.window = s_window;
 
 	/* Init celestial object */
-	*sInfos = TTF_RenderText_Blended(s_window.font, "Earth", colorFont);
+	*sInfos = TTF_RenderText_Blended(s_window.font, "Ground", colorFont);
 	initInfos(s_window.font, &rectInfos[0], sInfos[0], (WIN_PROJECTILE_WIDTH / 2) - sInfos[0]->w, rectObject.y + 15);
 
 	/* Get distance and time */