51��

Skip to content

Puzzle 73: Does Private Perkins end up facing the right way on parade?

19 August 2020

#73 Changing guard

Fifteen members of the King’s 99th Dragoons are standing on parade. “Right turn!” screams the sergeant, and each soldier makes a 90° turn. Unfortunately, many of the squad struggle to know their left from their right. After this manoeuvre, five soldiers end up facing left, including Private Perkins, who is in the middle of the row.

X X X X X X X P X X X X X X X

Any soldier that ends up face to face with another soldier now does a 180^° turn. This awkward ritual continues until no soldier can see…

Sign up to our weekly newsletter

Receive a weekly dose of discovery in your inbox. We'll also keep you up to date with 51�� events and special offers.

Sign up

or

Existing subscribers

More from 51��

Explore the latest news, articles and features

Health

The mysterious reason why women get hotter from age 18 to 42

51��

Editorial use only Mandatory Credit: Photo by 20thC.Fox/Everett/Shutterstock (1397228v) RISE OF THE PLANET OF THE APES Rise Of The Planet Of The Apes - 2011

Comment

This is the most underrated sci-fi film franchise of the 21st century

Culture

Shiver me timbers: Do we have to worry about space pirates now?

Comment

Shiver me timbers: Do we have to worry about space pirates now?

Regulars

CT42A4 POLYCYSTIC OVARY SYNDROME

Life

PMOS shows us why many scientific terms need to be renamed

Leader

1

Mystery of the ancient giant stone jars of Laos may have been solved

2

The Selfish Gene at 50: Why Dawkins’s evolution classic still holds up

3

The ‘doomsday’ glacier’s giant ice shelf is about to break away

4

After news about Oliver Sacks's "lies", we revisit his best-loved book

5

Wind-assisted cargo ships could more than halve shipping emissions

6

Solar farm on the ocean outperforms land-based solar in Taiwan

7

The distant world that is our best hope of finding alien life

8

We may finally know why dinosaurs like T. rex evolved tiny arms

9

How I used psychology to come back from the worst year of my life

10

Odd “butterfly” molecule could lead to new parts of the quantum realm