The last day for sending in solutions to the live problems is Monday 15 May.
Square it
Players take it in turns to choose a dot on the grid. The winner is the first to have four dots that can be joined to form a square.
Parallelogram it
Players take it in turns to choose a dot on the grid. The winner is the first to have four dots that can be joined to form a parallelogram.
Tilted squares
It's easy to work out the areas of most squares that we meet, but what if they were tilted?
Rhombus it
Players take it in turns to choose a dot on the grid. The winner is the first to have four dots that can be joined to form a rhombus.
Square coordinates
A tilted square is a square with no horizontal sides. Can you devise a general instruction for the construction of a square when you are given just one of its sides?
Opposite vertices
Can you recreate squares and rhombuses if you are only given a side or a diagonal?