What is evolution but the result of countless mutations to genetic structures over time. Some mutations provide benefits such as the gift of flight, while others can be harmful, such as the burden of allergies. Birds are a beautiful result of evolution in my opinion, and there are plenty here tod...

I once wrote an answer to Unexpected hanging paradox that went something like this "In the context of the unexpected hanging paradox, being hung by surprise is defined to mean he couldn't deduce the day before he was hanged that he was going to be hung on that day. It is not defined to mean he co...

I scamper away at any sound, I'm the thing next to your desktop, waiting to be found. Change one letter and you are in me, Add one letter, take a spoonful, Yum! What a beauty.

The answer to this puzzle consists of three words with a total of 13 letters. Combining what you see below should lead you to the correct answer.

This is a fun puzzle I invented 50 years ago. ("Loops of Zen" is rather similar, idea-wise.) Here is a random solution (doesn't spoil much)... ...and here are the building blocks: Basic is a 3*3 square. Any B/W coloring of it that doesn't contain a 2*2 checkerboard gives a valid piece. (I.e. th...

The picture above shows two arrangements of four rectangular blocks, each labelled A to D. The arrangement on the left is the starting arrangement, the one on the right is the goal position. To solve this puzzle you need to slide the blocks around so that the starting arrangement is transformed ...

I was mucking around in the storeroom today when I should have been working. I had a square $20\times20$ cm piece of cardboard, and a roll of masking tape I'd been using (I can't remember the tape's width, but it was an integer number of centimetres). I started mindlessly wrapping the tape around...

The New York Times publishes a collection of variety puzzles each week, and new to the rotation recently is one called "Circuit Board". Here is an example of a puzzle (I added coordinates for sake of discussion): The puzzle is solved when "every point is connected to either one or three (never t...