* Sliding Block Puzzle *

** a.k.a. *** Fifteen Block Puzzle, 1-2-3 Puzzle, ABC Puzzle,
*

Tenderfoot's Caution, Countdown

* S. S. Adams Co., Asbury Park, NJ., "PAT. APP'D FOR 1927". *

(6.4 inches square by 5/8 inches thick cardboard box with 15 3/8 thick wood pieces;
directions are on the inside of the box top shown on the right above;
most of the right side of the box top edge is missing)

Start with the position shown above and slide the blocks to end with 1 and 3 exchanged and block 2 in its original position.
Described on pages 14-15 of the
*Filipiak book*
(where a 262 move solution is presented).
*Hordern's book*
presents a 136 rectilinear move solution
(135 straight-line moves)
and a 148 rectilinear move solution
(147 straight line moves)
to the harder problem of a final position where 1 and 3 are exchanged and all other pieces are in their original positions
(Hordern lists the number of straight-line moves as 1 and 2 more respectively becasue he starts with the leftmost yellow block one unit down).
Both of Hordern's solutions begin with the same 72 rectilinear moves;
the following three pages show these common moves and then the remaining moves for each solution.

**Sliding Block Puzzle Directions**

**Common Portion of Hordern's Two Solutions**
For both of Hordern's solutions,
here are moves
0, 2, 9, 12, 19, 21, 27, 30, 37, 44, 47, 50, 53, 55, 62, 65, 72;
these are all of the moves of the 2x2 pieces plus move 37:

**Remaining Moves For Hordern's First Solution**
For the remainder of Hordern's first solution,
here are moves
72, 79, 86, 93, 100, 104, 107, 110, 113, 115, 120, 123, 130
for the 2x2 pieces:

**Remaining Moves For Hordern's Second Solution**
For the remainder of Hordern's second solution,
here are moves
72, 74, 77, 80, 83, 90, 93, 102, 105, 111, 114, 117, 120, 129, 132, 139, 140
for the 2x2 pieces: