xHomework due April 13.

STS(k) is a Steiner Triple System on k points, or equivalently
in notation used in class, it is the same as a 2-(v,3,1) design.

Write a program which is able to construct some small Steiner
Triple Systems. In particular, it must be able to generate at
least one STS(13) and at least one STS(15).

You can use any algorithm you wish. Each of the following should
work for the task above: exhaustive search by backtracking, Stinson's
algorithm, GAs, simulated annealing. For this homework put main
effort into the correctness. Performance would be of more
importance for generating larger designs.

Submit a commented hardcopy of your program and a printout of at 
least two STS's constructed by your program (on 13 and 15 points).
Independently, send by email the STS's to spr in the format:

First line: b v k
Next b lines listing one block each, order of blocks is arbitrary.
The points in each block must be listed in increasing order.
Use only white space to separate items (no , . ; etc).

Sample STS(15), or a 2-(15,3,1) design.

35 15 3
 1  2  3 
 1  4  5 
 1  6  7 
 1  8  9 
 1 10 11 
 1 12 13 
 1 14 15 
 2  4  6 
 2  5  7 
 2  8 10 
 2  9 11 
 2 12 14 
 2 13 15 
 3  4  7 
 3  5  6 
 3  8 12 
 3  9 13 
 3 10 15 
 3 11 14 
 4  8 15 
 4  9 10 
 4 11 12 
 4 13 14 
 5  8 11 
 5  9 14 
 5 10 13 
 5 12 15 
 6  8 14 
 6  9 15 
 6 10 12 
 6 11 13 
 7  8 13 
 7  9 12 
 7 10 14 
 7 11 15