x = 0;
y = 1;

dx = 1;
dy = 0;

ddx = 0;
ddy = 0;

dt = 0.01;

for i=1:1000
   ddy = -9.8;
   
   dx = dx + ddx*dt;
   dy = dy + ddy*dt;

   x = x + dx*dt;
   y = y + dy*dt;

   if (x > 1) 
      dx = -abs(dx);
      end
   if (x < -1) 
      dx = abs(dx);
      end
   if (y < -1) 
      dy = abs(dy);
   end

   plot(x,y,'bo');
   xlim([-1,1]);
   ylim([-1,1]);
   pause(0.01);
   end