On Fri, 18 Feb 1994, Jan de Ruiter wrote:
>
> Sorry about not reporting this earlier, but my search for solutions for
> Rubiks Tangle 10x10 confirms the finding of Don Woods: no solutions!
>
[snip]
> we could re-define the puzzle as follows:
> find which four pieces to duplicate in order to find solutions for
> the 10x10.
> If the number of solutions varies depending on the choice, you could
> even add a restriction:
> find which four pieces to duplicate in order to find a set which has
> the minimum number of solutions for the 10x10.
^^^^^^^
The kind Mr. Rubik has already done that - the minimum is - ZERO!

The revised problem can be solved fairly easily using your program ( I
don't know, though, how long it takes to run to completion for the 10*10
case) - try to place only 99 tiles out of the 100 given tiles. You may
have several sub-solutions. It is then easy to determine for each of these
sub-solutions which tile you need to complete the 10*10 mosaic. If this
pattern has already been duplicated, i.e. you need THREE numbers of this
tile to find the complete solution, this sub-solution will not work and so
examine the next sub-solution .... Hopefully you find the solution this way.

After running the program for the 99 tiles, the additional time required
to solve the problem defined by you should not be significant because that
would be a linear process.

Anand.