You order chicken wings at KFC in the boxes of 6, 9 and 20. What is the largest number of wings that you cannot obtain by buying in any combination of the boxes?
Here is a Swiss Cross. You have to make two straight cuts in the figure so that it is divided into four congruent pieces. Also, you should be able to join these pieces into a square then. Can you accept this challenge?
In 2011, people playing Foldit, an online puzzle game about protein folding, resolved the structure of an enzyme that causes an Aids-like disease in monkeys. Researchers had been working on the problem for 13 years. The gamers solved it in three weeks.