11th Hour

Solution to the Music Room or Furniture Moving puzzle of the
11th Hour by Dolf Grunbauer

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Published in DLH 98 September 1998. All rights reserved
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It took me almost a week to solve this puzzle, and actually I
solved it first on a cardboard with cut out pieces. Also I
solved it backwards, that is trying to figure out how the
piano could be in front of the exit and how it would get there
passed the table. Due to the ASCII picture please look at it
with a constant width font and 8 spaces TABs. Anyway here is
my solution (not optimal):

Pi is piano
Ta is table
B1, B2, B3 and B4 are the benches
a, b, c, d are the chairs
Note: not all drawings are proportional correct due to ASCII
drawing limitation
Note: always move 1 spot, moving twice is indicated with &

+------------+ +------------+
|+-++----++-+| 1. Ta down |+-++----++-+| 11. B3 right
||B||PIA ||B|| 2. b down ||B||PIA ||B|| 12. b up & up
||1|| NO ||2|| 3. c down ||1|| NO ||2|| 13. a left & up
|+-++----++-+| 4. a right |+-++----++-+| 14. Ta left & left
|+-++-++-++-+| 5. d left |+-+ +-++-+| 15. c down & right
||a||b||c||d|| 6. B3 up ||B| |d||B|| 16. d down & down
|+-++-++-++-+| 7. B4 up ||3| |c||4|| 17. B4 right
|+-++----++-+| 8. Ta right |+-+ +-++-+| 18. B2 down
||B||Tabl||B|| 9. b down & left |+-++-++----+| 19. Pi right
||3|+----+|4|| 10. a down & down ||b||a||Tabl|| 20. B3 up
|+-+ +-+| |+-++-++----+|
+--+ +--+ +--+ +--+

+------------+ +------------+
|+-++-++----+| 21. B4 left |+-++-++----+| 31. Ta up
||B||B||PIA || 22. B2 left ||B||B||PIA || 32. a right & right
||1||3|| NO || 23. c up & up ||1||3|| NO || 33. b right & right
|+-++-++----+| 24. d right & up |+-++-++----+| 34. B2 down
|+-+ +-++-+| 25. Ta right & right |+-++-++-++-+| 35. B4 down
||b| |B||B|| 26. a down & right ||B||B||d||c|| 36. d left & left
||a| |4||2|| 27. b down & down ||4||2|+-++-+| 37. c left & left
|+-+ +-++-+| 28. B4 left |+-++-+ | 38. Ta up
|+----++-++-+| 29. B2 left |+-++-++----+| 39. b up & right
||Tabl||d||c|| 30. d left & up ||b||a||Tabl|| 40. B2 right
|+----++-++-+| |+-++-++----+|
+--+ +--+ +--+ +--+

+------------+ +------------+
|+-++-++----+| 41. B4 right |+-+ +----+| 51. B4 up & up
||B||B||PIA || 42. d down & down ||c| |PIA || 52. d up & up
||1||3|| NO || 43. B1 down & down |+-+ | NO || 53. B1 right
|+-++-++----+| 44. B3 left |+-+ +----+| 54. B3 down & down
|+-++-++----+| 45. c up (once!) ||B|+-++----+| 55. c down & down
||d||c||Tabl|| 46. B4 up ||3||B||Tabl|| 56. B4 left
|+-++-++----+| 47. d right |+-+|4|+----+| 57. d up (once!)
|+-+ +-++-+| 48. B1 down |+-++-++-++-+| 58. c right
||B| |B||b|| 49. B3 down ||B|+-+|B||b|| 59. B4 down
||4| |2||a|| 50. c up & left ||1||d||2||a|| 60. d up & left
|+-+ +-++-+| |+-++-++-++-+|
+--+ +--+ +--+ +--+

+------------+ +------------+
|+-+ +----+| 61. c up & up |+-++-++-++-+| 71. B3 up
||d| |PIA || 62. B1 up & up ||B||B||d||c|| 72. B2 up
|+-+ | NO || 63. B2 left ||4||1|+----+| 73. b left & left
|+-+ +----+| 64. b left & down |+-++-+|PIA || 74. a left & left
||B|+-++----+| 65. Ta down | | NO || 75. Ta down
||4||c||Tabl|| 66. Pi down | +----+| 76. Pi down
|+-++-++----+| 67. c right & right | +----+| 77. d down & right
|+-++-++-++-+| 68. d right & right |+-++-+|Tabl|| 78. B1 right
||B||B||B||b|| 69. B4 up ||B||B|+-++-+| 79. B2 up & up
||3||1||2||a|| 70. B1 up ||3||2||b||a|| 80. Pi left
|+-++-++-++-+| |+-++-++-++-+|
+--+ +--+ +--+ +--+

+------------+ +------------+
|+-++-++-++-+| 81. d down & down |+-++-++-++-+| 91. b right & right
||B||B||B||c|| 82. c down & down ||B||B||B||B|| 92. Pi down
||4||2||1||d|| 83. B1 right ||3||4||2||1|| 93. d left & left
|+-++-++-++-+| 84. B2 right |+-++-++-++-+| 94. c left & left
|+-++----+ | 85. B4 right |+----+|d||c|| 95. Ta up
||B||PIA | | 86. B3 up & up ||PIA |+-++-+| 96. b up & right
||3|| NO | | 87. Pi left || NO ||Tabl|| 97. Pi right
|+-++----+ | 88. d left & up |+----++----+| 98. Pi down & out
|+-++-++----+| 89. Ta up |+-+ +-+|
||b||a||Tabl|| 90. a right right ||b| |a||
|+-++-++----+| |+-+ +-+|
+--+ +--+ +--+ +--+