杏吧原创

Advertisement

Curiosity Engine
Events
Tours

Explore by section

News
Features
杏吧原创
Podcasts
Video
Comment
Culture
Games
This week’s magazine

Explore by subject

Health
Space
Physics
Technology
Environment
Mind
Humans
Life
Mathematics
Chemistry
Earth
Society

Explore our products and services

Curiosity Engine
Events
Tours

Manage your subscription

Check your subscription status, update your details and more.

Manage your subscription

Your account
Account settings
Your newsletters
Subscriber benefits
Sign out

BrainTwister #103: O difference tree

By Peter Rowlett

Advertisement

Sign up to our weekly newsletter

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

More BrainTwisters

Your weekly dose of logical and mathematical puzzling.

BrainTwister

BrainTwister #124: Odd sums

29 April 2026
BrainTwister

BrainTwister #123: No repeats

22 April 2026
BrainTwister

BrainTwister #122: Squares and cubes

15 April 2026
See all BrainTwisters

Advertisement

Download the app

Find us on social media

Subscriptions

Subscriber benefits
Student & graduate

Support

Contact Us
FAQs
About us
Press room
Write for us

Tools

Events
Syndication
RSS feeds

Legal and privacy

Complaint policy
Privacy policy
Cookie policy
Terms & conditions
Cookie Settings

© Copyright 杏吧原创.