Left: The large rectangle is plastic and can be split into a square (blue) and two plastic rectangles (red and {green).
Centre: The two arcs drawn in each square.
Right: A Harriss spiral.
Image: Chalkdust.
More from Chalkdust
On conditional probability: Cards, Covid, and Crazy Rich Asians
Madeleine Hall explores the sometimes counterintuitive consequences of conditional probability to our everyday lives.The phantom parabola
Zoe Griffiths investigates paranormal quadraticsPrize crossnumber, Issue 07
Win £100 of Maths Gear goodies by solving our famously fiendish crossnumberWinning the Chalkdust coin game
How to win a game when your expected score is 0Crossnumber winners, issue 04
Are you a winner?100 years with the Sierpinski triangle
Three ways to obtain and generalise a beautiful fractal