Logic Grid

Four categories with four items each. The grid now has six sub-grids instead of three, and the clue count jumps to 8–10. More importantly, conditional clues appear: "the teacher drives a Honda" doesn't tell you who the teacher is, so you can't act on it until you've narrowed that down elsewhere.

Cross-referencing becomes necessary at this level. If you know Alice = Teacher and Teacher = Honda, you need to mark Alice = Honda in the separate Person/Car sub-grid. The grid handles some propagation automatically, but you'll still need to spot when a new match in one sub-grid creates opportunities in another.

A good approach: process all direct clues first, then loop through the conditional clues repeatedly. Each pass through the grid resolves more information, and conditionals that were useless on the first pass become actionable on the second or third. If you finish all clues and the grid isn't complete, scan for hidden singles — rows or columns with only one empty cell left.

Ready for bigger grids? The hard level adds a fifth item to each category, which makes elimination chains longer and cross-referencing more layered.