福爾摩斯Sherlock Holmes' problem (students' version)
What is the secret?
How is the square piece 'lost'?
worksheet: Sherlock Holmes
worksheet: 64 vs 65
Curry's Paradox (柯里悖論)
Explanation
More Reading
Cut-The-Knot
https://www.cut-the-knot.org/Curriculum/Fallacies/CurryParadox.shtml
The National University of Singapore
https://sms.math.nus.edu.sg/smsmedley/Vol-32-2/PSLE 2005 and Curry's Paradox (Helmer Aslaksen).pdf