Nine dots are arranged in the 2 × 2 square grid shown. The arrow points north.
Harry and Victoria take it in turns to draw a unit line segment to join two dots in the grid.
Harry is only allowed to draw an east-west line segment, and Victoria is only allowed to draw a north-south line segment. Harry goes first.
A point is scored when a player draws a line segment that completes a 1 × 1 square on the grid.
Can either player force a win, no matter how the other person plays?
Sign in or create an account to reveal answers, view the solution, and save your progress. Create a free account to unlock practice and keep track of your work.
Hamilton Mathematical Olympiad 2019 (2019)
One puzzle per day. Cryptarithm, Magic Square, Summit. No sign-up required to play.
Play daily puzzle →Interactive problems and curated lessons—water pouring, magic squares, knight's tour, and more.
Browse library →See how you rank. Top solvers by problems solved correctly. Sign in to climb the ranks.
View leaderboard →