zero -> 0x1 -> zero
one -> 0x2 -> one
two -> 0x4 -> two
three -> 0x8 -> three
four -> 0x0 -> 
zero one two three four -> 0xf -> zero one two three
0xff -> 0x0 -> 
0xffffffff -> 0x0 -> 
0xffffffffffffffff -> 0x0 ->