"Galaxies" is the one I keep coming back to. It has the property that computer-generated instances of it are often satisfying, with distinct "aha" moments where

"Galaxies" is the one I keep coming back to. It has the property that computer-generated instances of it are often satisfying, with distinct "aha" moments where everything falls into place. That's not true for all logic puzzles -- many Nikoli-style puzzles can be clever when designed by humans but are tedious when designed by computers.