List All Subsets Of The Set {1,2,3,4}?

There are 16 of them:
{}, {1}, {2}, {3}, {4}, {1, 2}, {1, 3}, {1, 4}, {2, 3}, {2, 4}, {3, 4}, {1, 2, 3}, {1, 2, 4}, {1, 3, 4}, {2, 3, 4}, {1, 2, 3, 4}

{1} {2} {3} {4} {1,2} {1,3}  {1,4} {2,1} {2,3} {2,4} {3,1} {3,2} {3,4}