1 x 6 x 6 (1)
The 1x6x6 with only a single solution and no sub shapes within makes it the most difficult of the flat shapes. Quite the beast! You can, however, calculate which pieces are not used. If you draw a 6×6 grid and place the 'H' piece at any position it will be obvious that this piece cannot be used for this shape. Since the 'H' contains 5 black subcubes and only 2 white subcubes, other pieces can be calculated as not working as well since the 1x6x6 has an equal number of black and white subcubes.
The 'H' piece is really the Key to the CalmPlex MindBlock puzzle.
1 x 6 x 7 (31)
This 1x6x7 and the 1x6x8 below contain the 1x3x3 at the corner. They can also be solved using the 1x3x4 in the corner.
1 x 6 x 8 (37)
