A squares board doesn’t have to be the full 10-by-10 grid. The format scales down cleanly, and picking the right size is mostly a question of how many people are actually going to claim a square.
100 squares — the classic
Ten numbers across, ten down, one square per exact pair of last digits. This is the layout most people picture when they hear “squares board,” and it’s the right call for a full room or a season-long group where you want every square to mean exactly one thing.
50 squares — two numbers a row
Cut the rows in half and each square now covers two possible digits instead of one. Good for a mid-sized group that still wants some texture to the board without a hundred squares to keep track of.
25 squares — built for a small group
Both axes halved, so each square covers two digits in each direction — four total combinations. A handful of friends can fill a 25-square board in a minute, and every square still has a real, non-trivial shot at a period.
Which one to pick
A rough rule that holds up: pick a size close to your group’s headcount. A 25-square board with four people leaves most of it empty; a 100-square board with six people means most squares never get an owner. Somewhere near one square per person is the sweet spot — GridAction offers the common sizes first when you start a new board.