Given once, 2024

Nim, Hackenbush, and Friends

Who wins at Nim? Pairing, mirroring, powers of two, and a first taste of Hackenbush

Combinatorial games · Recreational mathematics

An introductory outreach talk, for school students.

Abstract

Draft, not yet checked by me

Two players take turns removing tokens from heaps, and whoever makes the last move wins. Who should win? Starting with one and two heaps, I build winning strategies for Nim through pairing and mirroring, and show that writing heap sizes as sums of powers of two settles every position. There is a token-sliding game that is Nim in disguise, and Red-Blue Hackenbush, where each player may only cut edges of their own colour. There is also an activity round of Toads and Frogs, Domineering, Traffic Jam, and Southwest Queen.