More from Chalkdust
Crossnumber winners, Issues 20–22
Did you solve it?
Christmas puzzles: the solutions
We reveal the solutions to our Christmas puzzles!
Top Ten: pictures of scorpions
The definitive chart of the best pictures of scorpions
The phantom parabola
Zoe Griffiths investigates paranormal quadratics
Pretend numbers
20 questions, the axiom of choice and colouring sequences.
Four ways Photoshop encourages thinking mathematically
How processes used in image editing are related to mathematics!