Get all your news in one place.
100’s of premium titles.
One app.
Start reading
The Guardian - US
The Guardian - US
Science
Alex Bellos

Can you solve it? Do you think like an engineer?

Pythagoras of Samos around 570 BC - 510 BC a
Pythagoras of Samos around 570 BC - 510 BC a Photograph: Alamy

Today’s puzzles are about deducing the mechanisms behind two extremely puzzling objects: a practical joke cup supposedly invented by Pythagoras and a vehicle that seemingly travels the wrong way.

1. Pythagoras’s Cup

Pythagoras, the Greek mathematician and mystic, is credited with devising a cup with the following properties:

1) If you pour it up to a certain level it behaves like a normal cup.

2) If you pour it beyond that level all of the liquid in the cup empties through a hole at the bottom of the cup.

Can you draw the mechanism inside the cup?

The solution is very simple and has no moving parts. (If you are a plumber you might find this very easy.)

The cup is a cute metaphor for moderation in life. Fill it up just a little too much and you will lose everything.

2. Backwards jalopy

Design a simple mechanism for a four-wheeled toy vehicle such that when you pull a piece of string backwards out the vehicle, the vehicle moves forward.

I’ll be back at 5pm UK with the answers. Please NO SPOILERS. Instead please discuss your favourite engineering-based practical joke objects.

UPDATE: Read the solutions here.

I’ve been setting a puzzle here on alternate Mondays since 2015. I’m always on the look-out for great puzzles. If you would like to suggest one, email me.

Sign up to read this article
Read news from 100’s of titles, curated specifically for you.
Already a member? Sign in here
Related Stories
Top stories on inkl right now
One subscription that gives you access to news from hundreds of sites
Already a member? Sign in here
Our Picks
Fourteen days free
Download the app
One app. One membership.
100+ trusted global sources.