I have to make a hollowed out Hour glass out of asterisks

[tyooo]

How do i hollow out this hour glass? I'm new and this is REALLY hard to me I've spent countless hours on the construction of multiple shapes and hollowing out is tough concept for me.

  for (r = 0; r < 6;r++)
	{
		for (s = 0; s < 0 + 1 * r;s++)
		{
			printf(" ");
		}
		for (a = 0; a < 11 - 2 * r;a++)
		{
			printf("*");
		}
		printf("\n");

	}

	for (r = 0; r < 5; r++)					//I couldn't find out how to only use 1 "", *, and \n but the right answer is shown
	{
		for (s = 0; s < 4 - 1 * r;s++)
		{
			printf(" ");
		}
		for (a = 0; a < 2 * r + 3; a++)
		{
			printf("*");
		}
		printf(" \n");
	}