Seal

This weekend, I played (or rather re-played) a puzzle that has seen a number of incarnations over the years. The puzzle is Naoaki Takashima's IPP36 Exchange Puzzle called Seal - Slide-Blocked Sliding Block Puzzle. 

Start Position

End Position

The original version of the SBSB with a garage and car theme was designed by Bill Cutler in 1987. Bill made a later version using the "seal and ball" theme and entered it in the 1988 Hikimi Wooden Puzzle Design Competition where he won the Grand Prize. Subsequently Tom Lensch also made versions of the original SBSB and his latest version is featured in one of my previous post, suing a "twin arrows" theme. 

Naoaki Takashima is a Japanese Puzzle collector who reputedly has the largest private collection of mechanical puzzles outside the USA/Europe and in Japan. His version of the SBSB for the Exchange is different from the original Bill Cutler and Tom Lensch versions in several respects:-

1. The design is an "upside down" version of the original.

2. The pieces are made of laser cut double layer glued acrylic and removable from the tray. You can't see it from the photos but there is a groove running along the inside bottom edge of the tray with two of the pieces having "notches". The Tom Lensch version is interlocking and pieces can't be removed. This feature is a God-send and very necessary if you are stuck halfway and want to reset it to the start position. Tom's version is not so easy.

3. Handy size of 11cm x 9cm for ease of carrying around.

SBSB made by Tom Lensch.
The pieces are un-removable, except for the holding piece

Like the previous versions, the Seal takes a minimum of 41 rectilinear moves to solve. The main notable feature is that the piece with the red ball restricts the movements of the other pieces depending on where the piece is at the moment, which have been described in my review of Tom Lensch's version of the SBSB. 

Although I have played with the SBSB nearly two years ago, it still took me a while to figure out the moves again with the Seal and several times I had to re-arrange the pieces and start from beginning. 

Perhaps the best part about this puzzle is that all the action (min. 41 moves or more) takes place within a simple looking 3 x 2 size grid, and involving five rectangular pieces only, moving one at a time left right up and down...incredible design feat here!

As far as I know, all the other versions of the SBSB are not currently available but perhaps Naoaki, like most puzzle exchangers, may have some copies still left over from IPP36 for sale.