# What Color Is the Dragon?

Credit: Antonio J. Manzanedo Two knights encounter a dragon, who quickly responds, “I am protected by the king’s decree.” Gray rational dragons and red predator dragons always tell the truth; red rational dragons and gray predator dragons always lie. What color is the dragon? Solution This is a puzzle from Norman D. Willis’ Challenging False […]

# Pun of the Weak: It’s Logical

Here’s a classic one: Two ladies argue with one another every day from their windows, across an intervening lane. They never agreed, which was to be expected of course, for they argued from different premises!

# What’s Next: A Pattern Recognition Puzzle

Can you determine the next pattern in this pattern sequence? Solution In every row, the three images depict lines with 0, 1 and 2 intersections. That is, each row must contain an image with 0 intersection, an image with 1 intersection, and an image with 2 intersections. The number of intersections of the images for […]

# Dissection Puzzle: From “E” To Square

Can you cut the E into seven pieces with just four straight cuts and reassemble the pieces into a square? Solution When I wrote that you need to cut it into seven pieces, it’s actually a hint. Did you figure it out? The letter “E” figure above is constructed using the seven tangram pieces. So, if you were able to figure […]

# The Hooded Man Paradox: Knowing And Not Knowing Your Brother At The Same Time

Eubulides of Miletus (c. 400 BC), a philosopher of the Megarian school and a student of Euclid of Megara (not to be confused with Euclid of Alexandria who compiled the Elements of Euclid), posed the following paradox: You say you know your brother. Yet when your brother is hooded you are unable to identify him. […]

# Introducing Raymond Smullyan

One day, when a speaker was introducing logician and puzzlist Raymond Smullyan, he remarked that “Professor Smullyan is unique.” Smullyan, who was feeling playful that day, said, “I’m sorry to interrupt you Sir but I happen to be the only one in the entire universe who is not unique.” On another event, Smullyan was introduced […]

# Constructing Rectangles With Jigsaw Puzzle

What is the smallest rectangle which can be made by using jigsaw pieces of these two shapes only? What is the next smallest such rectangle? What rectangles are possible using these shapes only? (Note: You can use no matter how many of these two jigsaw pieces as you see fit.)

# Lewis Carroll’s Weird Sylogisms

A syllogism is a form of logical argument in which a conclusion is drawn from two or more premises that are assumed to be true using deductive reasoning. For instance, 1. All men are mortal. 2. Socrates is a man. Therefore Socrates is mortal.