On Friday I posted this puzzle….

When the day after tomorrow is yesterday, today will be as far from Sunday as today was from Sunday when the day before yesterday is tomorrow. What day is today?

If you have not tried to solve it, have a go now. For everyone else the answer is after the break.

Today is Sunday!

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called **PUZZLED** and is available for the **Kindle **(UK here and USA here) and on the **iBookstore** (UK here in the USA here). You can try 101 of the puzzles for free here.

Sorry that this post is somewhat later than usual. I have been a tad busy. So, if you are visiting the Edinburgh Festival, I shall be presenting the premiere of my new interactive psychology-based show** Experimental.** Details here, and there is a little video about the show below…

So here is this weeks puzzle.

When the day after tomorrow is yesterday, today will be as far from Sunday as today was from Sunday when the day before yesterday is tomorrow. What day is today?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called **PUZZLED** and is available for the **Kindle **(UK here and USA here) and on the **iBookstore** (UK here in the USA here). You can try 101 of the puzzles for free here.

If you are up at the Edinburgh Festival, I shall be talking about the strange science of sleep and dreaming on August 14th. Do come along, much fun will be had. Details here.

On Friday I posted this puzzle. Two cyclists are racing around a circular track. Jon can race around the track in 6 minutes and Eric can race round in 4 minutes. They start the race on opposite sides of the track. How many minutes will it take before Eric overtakes Jon?

If you have not tried to solve it, have a go now. For everyone else the answer is after the break.

12 minutes – but how did you solve it?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called **PUZZLED** and is available for the **Kindle **(UK here and USA here) and on the **iBookstore** (UK here in the USA here). You can try 101 of the puzzles for free here.

If you are up at the Edinburgh Festival, I shall be talking about the strange science of sleep and dreaming on August 14th. Do come along, much fun will be had. Details here.

Here is this weeks puzzle. Two cyclists are racing around a circular track. Jon can race around the track in 6 minutes and Eric can race round in 4 minutes. They start the race on opposite sides of the track. How many minutes will it take before Eric overtakes Jon?

**PUZZLED** and is available for the **Kindle **(UK here and USA here) and on the **iBookstore** (UK here in the USA here). You can try 101 of the puzzles for free here.

So, to the puzzle. On Friday I set this puzzle…..

Can you create a 10-digit number, where the first digit is how many zeros in the number, the second digit is how many 1s in the number etc. until the tenth digit which is how many 9s in the number.

If you have not tried to solve it, have a go now. For everyone else, the answer is after the break.

One answer is 6210001000 – did you come up with any others?

**PUZZLED** and is available for the **Kindle **(UK here and USA here) and on the **iBookstore** (UK here in the USA here). You can try 101 of the puzzles for free here.

OK, onto the puzzle. Can you create a 10-digit number, where the first digit is how many zeros in the number, the second digit is how many 1s in the number etc. until the tenth digit which is how many 9s in the number.

Solution on Monday!

Photo by Gordon Rutter.

]]>I have just made this video containing 10 bets that you will almost win (kinda). About 1 min in I present one of my favourite puzzles – the vanishing square.

You can download your own version of the puzzle here.

So, the puzzle is….why does a square seem to vanish?

If you have not tried to solve it, have a go now. For everyone else the answer is after the break.

The following video explains the puzzle, albeit with a slightly different set of shapes. Basically, the top shape is not an exact triangle, and so when the pieces are rearranged, the area that makes up the ‘missing’ square are redistributed in a different way. Did you solve it?

**PUZZLED** and is available for the **Kindle **(UK here and USA here) and on the **iBookstore** (UK here in the USA here). You can try 101 of the puzzles for free here.

A very different type of puzzle this week. I have just made this video containing 10 bets that you will almost win (kinda). About 1 min in I present one of my favourite puzzles – the vanishing square.

You can download your own version of the puzzle here.

So, the puzzle is….why does a square seem to vanish?

**PUZZLED** and is available for the **Kindle **(UK here and USA here) and on the **iBookstore** (UK here in the USA here). You can try 101 of the puzzles for free here.

On Friday I set this puzzle…

Imagine the Earth is perfectly circular and has a circumference of 24,000 miles. If you had a piece of rope stretched around it, touching the floor, that rope would also be 24,000 miles long. If you were to add 3 feet to that rope and then make it hover above the ground until it’s a perfect circle again, approximately how far off the ground would it get?

If you have not tried to solve it, have a go now. For everyone else the answer is after the break….

The rope would raise 6 inches off the ground if you added 3 feet to it! Can anyone explain why and what is surprising about this answer?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called **PUZZLED** and is available for the **Kindle **(UK here and USA here) and on the **iBookstore** (UK here in the USA here). You can try 101 of the puzzles for free here.

Here is a lovely puzzle sent to me by Ashley F. Solution on Monday.

Imagine the Earth is perfectly circular and has a circumference of 24,000 miles. If you had a piece of rope stretched around it, touching the floor, that rope would also be 24,000 miles long. If you were to add 3 feet to that rope and then make it hover above the ground until it’s a perfect circle again, approximately how far off the ground would it get?

**PUZZLED** and is available for the **Kindle **(UK here and USA here) and on the **iBookstore** (UK here in the USA here). You can try 101 of the puzzles for free here.