21 into 16 best min fragment found: 11/2
  Cut up 21 sticks of length 16 like this:
    1 x (15/2 + 17/2)
    1 x (7 + 9)
    3 x (13/2 + 19/2)
    4 x (6 + 10)
    12 x (11/2 + 21/2)
  Reassemble as 16 sticks of length 21 like this:
    6 x (21/2 + 21/2)
    1 x (13/2 + 7 + 15/2)
    1 x (6 + 13/2 + 17/2)
    1 x (11/2 + 13/2 + 9)
    3 x (11/2 + 6 + 19/2)
    4 x (11/2 + 11/2 + 10)