Regular polygons and stars
Patterns of coloured stones
Splitting rectangles into squares as large as possible
Circles and circular rings
Pentominoes and similar puzzles
Thread patterns
Calculating with square numbers - Number cycles
Area divisions
Weighing in the triple system
Parquetry of regular 2n-corners using rhombuses
Geometric figures on chequered paper and on a square grid
Eye totals
The vanished square
Splitting rectangles into many different squares
Kissing Circles
Sums of powers
Pythagoras' theorem.