The squares of the six polyominoes depicted below are either filled or empty. What logic was used to determine whether a square filled?

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+--+--+--+--+--+ +--+--+ +--+--+
| | | | | |##|##| |##|##|
+--+--+--+--+ +--+--+--+--+ +--+--+
|##| |##| |##| | |##| | | |
+--+--+--+ +--+--+--+--+ +--+--+
| | |##| |##| |##|
+--+ +--+--+--+--+ +--+
|##| |##|
+--+--+ +--+--+--+
| |##| |##|
+--+--+ +--+--+--+--+ +--+
|##|##| |##| | | |
+--+--+ +--+--+--+--+ +--+
|##|##| |##|##| |##|
+--+--+--+--+ +--+--+ +--+--+--+
| | | | |##|##| | | | |
+--+--+--+ +--+--+ +--+--+--+
|##| | | |##| |##|
+--+--+--+ +--+--+--+