while (1)
{
	x = x + velocity_x;
	y = y + velocity_y;

	system("cls");
	for (i = 0; i < x; i++)
		printf("\n");
	for (j = 0; j < y; j++)
	{
		printf(" ");
	}
	printf(" O \n");
	printf("\n");
	Sleep(50);
	if ((x == top) || (x == bottom))
	{
		printf("\a");
		velocity_x = -velocity_x;
	}

	if ((y == left) || (y == right))
	{
		printf("\a");
		velocity_y = -velocity_y;
	}
}
return 0;