Not counting rotations and reflections,
for the 3x20, there are but two solutions, the other
one derived from the one shown by rotating the section
outlined in white by 180 degrees.
To see
"I" or "+"
based breakdowns, click on the Ppentominoes:
(some placements have unique solutions !)
the 2339 solutions of the 6x10
the 1010 solutions of the 5x12
the 368 solutions of the 4x15
congruent halves of the 6x10's
to refresh the sample solutions
of all four standard size puzzles.


The 6x10 rectangle has 2339 solutions, and some of them
have special properties, such as:
 Contain a 3x5, 4x5, or 5x6 rectangle,
in different positions and orientations.
 Contain a symmetric region which can be flipped.
Some have two !
 Contain two congruent regions which can be switched.
 Have a minimum (8) or maximum (12) pentominoes touching the edge.
(There are just two of the latter.)
There are many ways the 6x10 can be divided into two congruent parts.
Here are a few of them. How many can you solve ?
Which others can you find ?
Click on an image to switch it from outline to filledin, or viceversa.
