diff --git a/main.c b/main.c
new file mode 100644
index 0000000..9e05d68
--- /dev/null
+++ b/main.c
@@ -0,0 +1,408 @@
+//
+//  main.c
+//  physics
+//
+//  Created by Eric on 16/5/6.
+//  Copyright © 2016年 Bakantu Eric. All rights reserved.
+//
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <math.h>
+#include <GLUT/GLUT.h>
+#define E_G -9.8
+#define A_G 6.67259e-11
+#define o_MAX 16
+#define f_MAX 32
+#define X_WIN 400
+#define Y_WIN 400
+#define w_MAX 32
+#define Pi 3.1415926536
+#define CLEAN system("clear")
+#define GL_SILENCE_DEPRECATION
+
+typedef struct{
+    double x;
+    double y;
+    double mass;
+    int gravity;
+    int e_gravity;
+    double vx;
+    double vy;
+    double a_x;
+    double a_y;
+    int elasticity;
+} obj;
+
+typedef struct {
+    double size;
+    double angle;
+    double time;
+    obj *p_obj;
+} force;
+
+typedef struct {
+    double x0;
+    double y0;
+    double x1;
+    double y1;
+    int on;
+} wall;
+
+int opengl_init(int argc, const char * argv[]);
+int add_obj(obj *objs[o_MAX]);
+int add_force(obj *objs[o_MAX], force *forces[f_MAX]);
+int physics_engine(obj *objs[o_MAX],force *forces[f_MAX],wall *walls[w_MAX]);
+int print(obj *objs[o_MAX], force *forces[f_MAX]);
+int move_obj(obj *objs[o_MAX]);
+int delete_obj(obj *objs[o_MAX]);
+void o_display(void);
+void key_down(unsigned char key, int x, int y);
+void mouse_click(int button, int state, int x, int y);
+void keep_physics_engine(void);
+int set_wall(void);
+void w_display(void);
+int set_size(void);
+
+obj *i_objs[o_MAX];
+force *i_forces[f_MAX];
+wall *i_walls[w_MAX];
+int wall_point = 0;
+int p_wall = 0;
+int engine_on = 1;
+int settings = 0;
+double x_MAX = 1000, y_MAX = 1000;
+double ENGINE_TIME = 0.01;
+
+
+int main(int argc, const char * argv[]) {
+    for (int i = 0; i < o_MAX; i++) i_objs[i] = NULL;
+    for (int i = 0; i < f_MAX; i++) i_forces[i] = NULL;
+    for (int i = 0; i < f_MAX; i++) i_walls[i] = NULL;
+
+    CLEAN;
+    opengl_init(argc, argv);
+    //physics_engine(i_objs, i_forces);
+    for (int i = 0; i < o_MAX; i++) {
+        if(i_objs[i] != NULL) free(i_objs[i]);
+        if(i_forces[i] != NULL) free(i_forces[i]);
+        if(i_walls[i] != NULL) free(i_walls[i]);
+    }
+    return 0;
+}
+
+
+int add_obj(obj *objs[o_MAX]){
+    CLEAN;
+    int p_c = 0;
+    while (objs[p_c] != NULL) p_c++;
+    objs[p_c] = (obj *)malloc(sizeof(obj));
+    printf("X: ");
+    scanf("%lf",&objs[p_c]->x);
+    printf("Y: ");
+    scanf("%lf",&objs[p_c]->y);
+    printf("MASS: ");
+    scanf("%lf",&objs[p_c]->mass);
+    printf("IF EARTH_GRAVITY: ");
+    scanf("%d",&objs[p_c]->e_gravity);
+    printf("IF GRAVITY: ");
+    scanf("%d",&objs[p_c]->gravity);
+    printf("VX: ");
+    scanf("%lf",&objs[p_c]->vx);
+    printf("VY: ");
+    scanf("%lf",&objs[p_c]->vy);
+    //printf("IF ELASTICITY: ");
+    //scanf("%d",&objs[p_c]->elasticity);
+    fflush(stdin);
+    return 0;
+}
+
+int add_force(obj *objs[o_MAX], force *forces[f_MAX]){
+    CLEAN;
+    int p_c = 0, i_obj;
+    while (forces[p_c] != NULL) p_c++;
+    forces[p_c] = (force *)malloc(sizeof(force));
+    printf("SIZE: ");
+    scanf("%lf",&forces[p_c]->size);
+    printf("ANGLE: ");
+    scanf("%lf",&forces[p_c]->angle);
+    printf("TIME: ");
+    scanf("%lf",&forces[p_c]->time);
+    printf("OBJ: ");
+    scanf("%d",&i_obj);
+    if(objs[i_obj] != NULL) forces[p_c]->p_obj = objs[i_obj];
+    else forces[p_c]->p_obj = NULL;
+    fflush(stdin);
+    return 0;
+}
+
+
+int physics_engine(obj *objs[o_MAX],force *forces[f_MAX],wall *walls[w_MAX]){
+    for(int i = 0; i < o_MAX; i++){
+        double a_x = 0.0, a_y = 0.0;
+        if (objs[i] == NULL) continue;
+        if(fabs(objs[i]->x) > x_MAX || fabs(objs[i]->y) > y_MAX){
+            free(objs[i]);
+            objs[i] = NULL;
+            continue;
+        }
+        else{
+            if(objs[i]->e_gravity){
+                a_y += E_G * ENGINE_TIME;
+            }
+            if(objs[i]->gravity){
+                for (int k = 0; k < o_MAX; k ++){
+                    if ((objs[k] == NULL)||(k == i)) continue;
+                    else{
+                        double d_x = objs[k]->x - objs[i]->x;
+                        double d_y = objs[k]->y - objs[i]->y;
+                        double d_angle = atan(d_y / d_x);
+                        if (d_y < 0 && d_x < 0) {
+                            d_angle = -d_angle;
+                            d_angle -= Pi/2;
+                        }
+                        else  if (d_y > 0 && d_x < 0) {
+                            d_angle = -d_angle;
+                            if (d_x < 0) d_angle += Pi/2;
+                        }
+                        double dis = sqrt((d_x * d_x) + (d_y * d_y));
+                        double g_force =(A_G * objs[i]->mass * objs[k]->mass)/(dis * dis);
+
+                        a_x += (g_force * cos(d_angle)) / objs[i]->mass;
+                        a_y += (g_force * sin(d_angle)) / objs[i]->mass;
+                    }
+                }
+            }
+        }
+        for (int k = 0; k < f_MAX; k++){
+            if (forces[k] == NULL)continue;
+            else if (forces[k]->p_obj == objs[i]){
+                a_x += (forces[k]->size * cos(forces[k]->angle)) / objs[i]->mass *ENGINE_TIME;
+                a_y += (forces[k]->size * sin(forces[k]->angle)) / objs[i]->mass *ENGINE_TIME;
+            }
+            if(forces[k]->time > 0) forces[k]->time -= ENGINE_TIME;
+            if(forces[k]->time <= 0) {
+                free(forces[k]);
+                forces[k] = NULL;
+            }
+        }
+        objs[i]->a_x = a_x;
+        objs[i]->a_y = a_y;
+    }
+    usleep(1000000*ENGINE_TIME);
+    move_obj(objs);
+    return 0;
+}
+
+int print(obj *objs[o_MAX], force *forces[f_MAX]){
+    CLEAN;
+    printf("#OBJ:\n");
+    for (int i = 0; i < o_MAX; i++){
+        if (objs[i] != NULL){
+            printf("OBJ[%d](%p): (%lf, %lf) \nMASS: %lf\n\n",i,objs[i],objs[i]->x,objs[i]->y,objs[i]->mass);
+            glVertex2f(objs[i]->x/x_MAX, objs[i]->y/y_MAX);
+        }
+    }
+    printf("\n#FORCE:\n");
+    for (int i = 0; i < o_MAX; i++){
+        if(forces[i] != NULL){
+            printf("FORCE[%d]: SIZE:%.5lf ANGLE: %.5lf P_OBJ: %p\n, TIME: %.2lf",\
+                   i,forces[i]->size,forces[i]->angle,forces[i]->p_obj,forces[i]->time);
+        }
+    }
+    printf("\n");
+    return 0;
+}
+
+int move_obj(obj *objs[o_MAX]){
+    for (int i = 0; i < o_MAX; i++){
+        if (objs[i] == NULL) continue;
+        if (objs[i]->a_x != 0){
+            double a_x = objs[i]->a_x;
+            objs[i]->x += objs[i]->vx + 0.5 * a_x * ENGINE_TIME * ENGINE_TIME;
+            objs[i]->vx += a_x;
+        }
+        if (objs[i]->a_y != 0){
+            double a_y = objs[i]->a_y;
+            objs[i]->y += objs[i]->vy + 0.5 * a_y * ENGINE_TIME * ENGINE_TIME;
+            objs[i]->vy += a_y;
+        }
+
+    }
+    return  0;
+}
+int delete_obj(obj *objs[o_MAX]){
+    CLEAN;
+    int d_obj;
+    printf("DELETE OBJ: ");
+    scanf("%d",&d_obj);
+    if (objs[d_obj] != NULL){
+        free(objs[d_obj]);
+        objs[d_obj] = NULL;
+    }
+    fflush(stdin);
+    return 0;
+    
+}
+
+int opengl_init(int argc, const char * argv[]){
+    glutInit(&argc, (char **)argv);
+    glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
+    glutInitWindowPosition(X_WIN/2, Y_WIN/2);
+    glutInitWindowSize(X_WIN, Y_WIN);
+    glutCreateWindow("Physics");
+    glutDisplayFunc(&o_display);
+    glutIdleFunc(&keep_physics_engine);
+    glutKeyboardFunc(&key_down);
+    glutMouseFunc(&mouse_click);
+    glutMainLoop();
+    return 0;
+}
+
+void o_display(void){
+    glClearColor(1.0f,1.0f,1.0f,1.0f);
+    glClear(GL_COLOR_BUFFER_BIT);
+    glPointSize(4.0f);
+    
+    glBegin(GL_POINTS);
+    glColor3f(0,255,0);
+    for (int i = 0; i < o_MAX; i++){
+        if (i_objs[i] != NULL){
+            glVertex2f(i_objs[i]->x/x_MAX, i_objs[i]->y/y_MAX);
+        }
+    }
+    glEnd();
+    
+    glLineWidth(2);
+    glDisable(GL_LINE_STIPPLE);
+    glBegin(GL_LINES);
+    for (int i = 0; i < w_MAX; i++){
+        if (i_walls[i] != NULL){
+            if (i_walls[i]->on == 1){
+                glVertex2f(i_walls[i]->x0/X_WIN*2,i_walls[i]->y0/Y_WIN*2);
+                glVertex2f(i_walls[i]->x1/X_WIN*2,i_walls[i]->y1/Y_WIN*2);
+            }
+        }
+    }
+    glEnd();
+    glFlush();
+}
+
+void key_down(unsigned char key, int x, int y){
+    if(key == 's'){
+        CLEAN;
+        int ifnot = 1;
+        char input = '\0';
+        while (ifnot){
+            printf("DEALWHITH:\n");
+            printf("1.ADD OBJ\n");
+            printf("2.ADD FORCE\n");
+            printf("3.EXIT PROGRAM\n");
+            printf("4.DELETE OBJ\n");
+            printf("5.SET WALL\n");
+            printf("6.SET SIZE\n");
+            printf("q.START ENGINE\n");
+            fflush(stdin);
+            input = getchar();
+            fflush(stdin);
+            switch (input) {
+                case '1':
+                    add_obj(i_objs);
+                    break;
+                case '2':
+                    add_force(i_objs, i_forces);
+                    break;
+                case '3':
+                    exit(0);
+                    break;
+                case '4':
+                    delete_obj(i_objs);
+                    break;
+                case '5':
+                    engine_on = 0;
+                    settings = 1;
+                    wall_point = 0;
+                    p_wall = 0;
+                    while (i_walls[p_wall] != NULL) p_wall++;
+                    i_walls[p_wall] = (wall *)malloc(sizeof(wall));
+                    i_walls[p_wall]->on = 0;
+                    ifnot = 0;
+                    break;
+                case '6':
+                    set_size();
+                    break;
+                case 'q':
+                    ifnot = 0;
+                    break;
+                default:
+                    break;
+            }
+            CLEAN;
+        }
+    }
+}
+
+void keep_physics_engine(void){
+    if (engine_on) {
+        physics_engine(i_objs, i_forces,i_walls);
+        print(i_objs,i_forces);
+    }
+    else{
+        set_wall();
+    }
+    o_display();
+}
+int set_wall(void){
+    if (wall_point == 2){
+        engine_on = 1;
+        settings = 0;
+        wall_point = 0;
+        i_walls[p_wall]->on = 1;
+    }
+    return 0;
+}
+
+void mouse_click(int button, int state, int x, int y){
+    if (state == GLUT_DOWN){
+        if (!engine_on && settings == 1 && button == GLUT_RIGHT_BUTTON){
+            printf("%d,%d\n",x-X_WIN/2,-(y-Y_WIN/2));
+            printf("x = %d y = %d\n",x,y);
+            if(wall_point < 2){
+                if(wall_point == 0){
+                    i_walls[p_wall]->x0 = (x-X_WIN/2);
+                    i_walls[p_wall]->y0 = -(y-Y_WIN/2);
+                }
+                else if(wall_point == 1){
+                    i_walls[p_wall]->x1 = (x-X_WIN/2);
+                    i_walls[p_wall]->y1 = -(y-Y_WIN/2);
+                }
+                wall_point++;
+            }
+        }
+    }
+}
+
+void w_display(void){
+    glClear(GL_COLOR_BUFFER_BIT);
+    glPointSize(4.0f);
+    glBegin(GL_POINTS);
+    for (int i = 0; i < o_MAX; i++){
+        if (i_objs[i] != NULL){
+            glVertex2f(i_objs[i]->x/x_MAX, i_objs[i]->y/y_MAX);
+        }
+    }
+    glEnd();
+    glFlush();
+}
+
+int set_size(void){
+    CLEAN;
+    printf("XMAX: ");
+    scanf("%lf",&x_MAX);
+    printf("YMAX: ");
+    scanf("%lf",&y_MAX);
+    printf("ENGINE_TIME: ");
+    scanf("%lf",&ENGINE_TIME);
+    return 0;
+}