Any square can be formed with game pieces or marbles, The first square has two rows of each 2 Stones, the second has three stones in each of the three rows, and so on. The number of all stones, that form a square, is called the square number. 2 · 2, 3 · 3, 4 · 4, and each additional number, multiplied by itself gives a square number. The ancient Greeks found, that there is a relationship between square numbers and odd numbers. (An odd number is a number, the not through 2 can be shared.)
When you take the sum of any group of consecutive odd numbers and catch 1 an, you always get a square number.
1+3 = 4 = 2 · 2 = 2²
1 + 3 + 5 = 9 = 3 · 3 = 3²
1+ 3 + 5 + 7 = 16 = 4 · 4 = 4²
Brand: The number of odd numbers to add is the same as the number, which is squared.