First, I shall call designate each of the six figures given with a
different number, as shown below:

1:  *
     **
     ***
     ***
     *

2:  ***
    ****
     ***

3:  ****
     ****
        **
        **

4:       *
     *****
     ****

5:  *****
     ****
        *

6:         *
          **
        **
   *****

And the twelve pentominoes shall bew referred to by their common
single-letter names:

I: *****

L: ****
      *

Y: ****
     *

N: ***
     **

V:  ***
    *
    *

T: ***
    *
    *

P: ***
    **

F: *
   ***
    *

U: ***
   * *

X:   *
    ***
     *

Z: *
   ***
     *

W: **
    **
     *

(Apologies for the ASCII art, which may not show up well on the screen,
but you should get the idea what all the shapes look like.)

Now, of the six given shapes, the only one which can include N without
leaving some squares isolated is 6, and its other shape must be L. This
means only 5 can include I, which must be paired with Y. T must now be
paired in 1 with W. Z must be in 3 with V. U must be in 2 with X. And
that leaves F and P in 4, bu elimination. Since F and P can indeed be
paired to form 4, that solves the problem.

Darrel C Jones
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