Logic Puzzle Club

LITS of the week: week 5

The full logical solve of the hard LITS for September 29 to October 5, 2026, 10 × 10. 47 steps, 6 techniques, no guessing. Step through it, or jump to any step below.

Region overlap. Every tetromino that still fits in this region covers r1c3 and r2c3.
Step 1 of 47

Every step

  1. Every tetromino that still fits in this region covers r1c3 and r2c3.

  2. Every tetromino that still fits in this region covers r1c5 and r1c6.

  3. Every tetromino that still fits in this region covers r1c8 and r1c9.

  4. Every tetromino that still fits in this region covers r2c7, r3c7 and r3c8.

  5. Every tetromino that still fits in this region covers r3c10 and r4c10.

  6. Every tetromino that still fits in this region covers r5c2 and r6c2.

  7. Every tetromino that still fits in this region covers r5c8.

  8. Every tetromino that still fits in this region covers r6c7, r7c6, r7c7 and r7c8. Only one fit is left: a T.

  9. Every tetromino that still fits in this region covers r8c1, r9c1 and r10c1.

  10. Every tetromino that still fits in this region covers r10c3.

  11. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r2c1 and r3c1, and none covers r6c1 and r7c1.

  12. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r3c3.

  13. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r2c5.

  14. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r1c7 and r1c10, and none covers r2c8. Only one fit is left: an I.

  15. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r4c8, and none covers r2c6. Only one fit is left: an S.

  16. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r3c9.

  17. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r6c4.

  18. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r5c7 and r5c9, and none covers r4c7 and r4c9.

  19. Fits that would finish a 2×2 block of shading are out. Every fit left in this region misses r6c6.

  20. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r7c9 and r8c9, and none covers r6c8, r8c6, r8c7 and r8c8.

  21. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r10c9, and none covers r7c10.

  22. Fits that would touch a tetromino of the same shape next door are out. Every fit left in this region covers r2c10, and none covers r2c9. Only one fit is left: a T.

  23. Fits that would touch a tetromino of the same shape next door are out. Every fit left in this region covers r3c5.

  24. Fits that leave a neighbouring region no tetromino that works beside them are out. Every fit left in this region covers r4c1, and none covers r1c2.

  25. Fits that leave a neighbouring region no tetromino that works beside them are out. Every fit left in this region covers r8c5.

  26. Fits that leave a neighbouring region no tetromino that works beside them are out. Every fit left in this region covers r6c9 and r6c10, and none covers r9c8 and r9c9. Only one fit is left: an L.

  27. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r5c6, and none covers r5c10. Only one fit is left: an I.

  28. Fits that would touch a tetromino of the same shape next door are out. Every fit left in this region covers r10c8, and none covers r8c10.

  29. Fits that would cut some shading off from the rest are out. Every fit left in this region covers r10c7, and none covers r9c10.

  30. Fits that leave a neighbouring region no tetromino that works beside them are out. Every fit left in this region covers r10c4 and r10c5, and none covers r8c3 and r9c2.

  31. Suppose r2c2 is left white. Following the rules from there, a region would have no tetromino that fits. So it is shaded.

  32. Every tetromino that still fits in this region misses r3c2.

  33. Fits that would touch a tetromino of the same shape next door are out. Every fit left in this region covers r2c4, and none covers r1c4. Only one fit is left: an S.

  34. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r3c6, r4c5 and r5c5, and none covers r3c4 and r4c6. Only one fit is left: an L.

  35. Fits that would finish a 2×2 block of shading are out. Every fit left in this region misses r4c4.

  36. Fits that leave a neighbouring region no tetromino that works beside them are out. Every fit left in this region covers r8c4, and none covers r6c5.

  37. Suppose r4c2 is left white. Following the rules from there, a region would have no tetromino that fits. So it is shaded.

  38. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r1c1, and none covers r5c1. Only one fit is left: an I.

  39. Suppose r4c3 is left white. Following the rules from there, a region would have no tetromino that fits. So it is shaded.

  40. Every tetromino that still fits in this region misses r5c3.

  41. Fits that would touch a tetromino of the same shape next door are out. Every fit left in this region covers r5c4 and r6c3, and none covers r7c2.

  42. Fits that would cut some shading off from the rest are out. Every fit left in this region covers r10c2, and none covers r8c2. Only one fit is left: an L.

  43. Fits that would touch a tetromino of the same shape next door are out. Every fit left in this region covers r10c6, and none covers r9c3. Only one fit is left: an I.

  44. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r7c5, and none covers r9c6.

  45. Fits that would finish a 2×2 block of shading are out. Every fit left in this region covers r7c3, and none covers r7c4. Only one fit is left: an S.

  46. Fits that would touch a tetromino of the same shape next door are out. Every fit left in this region covers r9c4, and none covers r9c5. Only one fit is left: an S.

  47. Fits that would touch a tetromino of the same shape next door are out. Every fit left in this region covers r9c7, and none covers r10c10. Only one fit is left: an L.