Some sliding block puzzles

The classic "15 puzzle" 15 puzzle slow version
The "14 puzzle", using equilateral triangles 14 puzzle slow version
Objective: Remove the 1-tile. Then arrange the others all in the right order ( 2 3   4 5 6   7 8 9 ) and all the right way up. Gothic arch (numeric)
Objective: Swap the two middle (orange and gold) disks in the bottom row, so that they're all in spectral cyclic order, with blue at the top. The black dots and rings on the disks are to help colour-blind users. Coloured disks
Objective: Get all the tiles the right way up (with "a" and "b" tilted slightly inwards, as "b" already is), and in the right order, a b   c d e   f g h. Gothic arch (alpha)
With this one, you can do any permutation, and you can't rotate anything by more than 20°. As a challenge, choose any two blocks and try to interchange them while ending with the rest back where they started. Cookie jar

This page provides some sliding block puzzles, presented as animated SVG files.

The animation does not work for the images as seen on this page. To use one, click on the gold-coloured link, and your browser will open the image, as a functioning animated SVG, in a new browser tab.

To operate one of these puzzles, you move a tile by tapping it, so long as it has somewhere it can move to.

You remove a tile, if instructed to, by moving the mouse over it, or by tapping it, in the same way as you select it to move.

The animation of a tile moving to its new position is set to ¼ of a second. For some puzzles there is also a slow version, identical except that the animation takes three seconds.

If you make the browser window wider than it is tall, you'll see

• For puzzles with an objective, the target state. You achieve the objective by moving the blocks so that they look like that target.
• A count of the number of moves you've made. Moves are counted using definition 1 as defined by Edward Hordern: "Slide one piece only in any direction or combination of directions". If you undo a move, it is subtracted from the count; it's always possible to get the count back to 0 by undoing all your moves in the right order.
• A way of toggling the puzzle between "tap to move" (the default) and "hover to move". If there's a target state shown, you toggle by clicking on a tile in it; otherwise, by clicking on a button.

Hordern puzzles

This site also offers 35 SVG versions of sliding block puzzles listed by Edward Hordern in his book Sliding Piece Puzzles, O.U.P, 1986.

Comments

I had a design for a sliding block puzzle, and planned to implement it in wood. But to make sure that it worked as I planned, I made prototypes in cardboard. Building a usable cardboard prototype, and sliding its cardboard blocks, were both harder than I expected. So I decided to build a prototype in animated SVG instead. I started by doing the 15-puzzle,

My animated SVG of the 15 puzzle was easier to build than I had expected, and more fun to use than I had anticipated. It now seems likely that I won't be using wood at all: building a puzzle in animated SVG is easier than building one in wood, doesn't risk loss of blood when my chisel slips, and allows the whole world to play with it, not just one owner.

So far, I have designed only puzzles that could be implemented in wood.