Mathematical Maelström

For some calculation you must visit

http://www.plutopuzzles.com/puzzles/maelstrom/maelstrom.htm

Architect

On http://www.obrazkilogiczne.pl/eindex.php you find every friday 3 new architect (= tents)
puzzles. There are also 2 japanese puzzles (=pic-a-pix) and 3 multidots (=slitherlinks) in
the weekly puzzle mix

Trizm

Trizm is a sudoku variation

You have to fill in the blank small triangles with a 1 - 9

Each number can appear only once in each side, inner triangle, and colored crossbar

You find 5 daily puzzles on http://www.trizmpuzzle.com/

Colour sudoku

In Colour Sudoku, instead of filling in the numbers 1 to 9 in each of the 3 by 3 blocks, you must enter 1 to 9 in the 9 boxes of each colour - i.e. there are nine yellow boxes, and the yellow boxes must contain the digits 1 to 9.

You find a daily puzzle on: http://www.coloursudoku.com/

Trigon

The diagrammatic shapes show a set of triangular dominoes made up from the numbers in the table. The number in the centre of each domino show the sum of the numbers on its edges. Where one domino meets another the numbers are the same, so in order to save writing it twice, a space has been left where they meet. By using logic, fill in the numbers around each triangular domino.If you register at http://www.trigonpuzzles.com/ you get a free e-book with puzzles.

HaniDoku

HaniDoku is another sudoku variation.

More Information and a daily puzzle are on

http://www.hanidoku.com/

Sudoku variants

Goto http://www.hexapuzzle.hu/sudokuvariants/ for these strange sudoku variants

There are samples and a 'how to solve' page