Puzzle Miscellany

Logic Puzzle Grids

Logic puzzles are solved with the aid of logic grids. A standard completed grid is shown in figure A. I can visualize the relationships better and solve the puzzle faster if I draw curved lanes connecting the matching rows and columns of the subgrids (figure B) . I also find it helpful to color the "true" markers that go together because they are in the same rows and columns (figure C).

M-Heart-8

Source: I first saw the M-Heart-8 puzzle in print, perhaps in the 1980s or 1990s, but I don't remember where. It was popularized in The Simpsons on TV (1998, episode title "Lisa the Simpson") and in The Oxford Murders book (2003) and movie (2008). If you know a source earlier than 1998, please let me know.