 If a number has a circle around it, it means that, while that number of cubes is the total amount in the row/column, they will be split up into two groups (for example, a 4 with a circle around it will be in two groups of either 1 and 3 or 2 and 2).If a number has a square around it, the cubes will be split up into three or more groups.If there are no numbers on a row or column, there are no rules concerning how many cubes belong there.