The squares of the six polyominoes depicted below are either filled or empty. What logic was used to determine whether a square filled?
+--+--+--+--+--+ +--+--+
|##| |##| |##| |##|##|
+--+--+--+--+--+ +--+--+ +--+--+
| | | | | |##|##| |##|##|
+--+--+--+--+ +--+--+--+--+ +--+--+
|##| |##| |##| | |##| | | |
+--+--+--+ +--+--+--+--+ +--+--+
| | |##| |##| |##|
+--+ +--+--+--+--+ +--+
|##| |##|
+--+--+ +--+--+--+
| |##| |##|
+--+--+ +--+--+--+--+ +--+
|##|##| |##| | | |
+--+--+ +--+--+--+--+ +--+
|##|##| |##|##| |##|
+--+--+--+--+ +--+--+ +--+--+--+
| | | | |##|##| | | | |
+--+--+--+ +--+--+ +--+--+--+
|##| | | |##| |##|
+--+--+--+ +--+--+--+
Labelling the six polyominoes from left to right, top row then bottom row
A B C
D E F
I notice that F fits inside A, with pattern intact. C, upside down, fits with E, pattern intact. D, when inverted, is like E, except one square is relocated, and the patterns in the squares adjacent to the relocated squares have changed accordingly.
Apparently, some rule is being applied, but I'm not seeing it clearly yet.
Observations
