The 163 twins of size 4x4 that have only 1 solution:
The 102 twins of size 4x4 that have 2 to 19 solutions:
The 100 twins of size 3x5 that have 1 to 24 solutions:
The 69 twins of size 5x3 with 1 to 23 solutions:
The 30 twins of sizes 2x6, 2x7 and 3x4, with 1 to 18 solutions:
Arrange the 9 Shardinaires-9 tiles in a 3x3 array so that every straight row of threehorizontal or verticalcan form a symmetrical figure. There are a total of 29 ways to build a magic 3x3. Twelve of them are in the booklet. Here are the other 17. That's a total of 174 symmetrical trios.
Amazing, aren't they? Pick any square and find all 6 of its solutions. Yes, a human can do it without a computer. Surprise yourself.