Stack S: 5.5 "five" 5 4.5 "four" 4 3.5 "three" 3 2.5 "two" 2 1.5 "one" 1 size = 15 Top of the stack: 4.5 Stack S: 4.5 "four" 4 3.5 "three" 3 2.5 "two" 2 1.5 "one" 1 size = 12