The blue thing below is my painting called "The Birth of Square Numbers from the Triangular Numbers". If you have problems seeing the square numbers (1, 4, 9 and 16), then count the white triangles (each one of which is marked by a red dot) between any three blue circles. If you have problems seeing the triangular numbers (3, 6, 10 and 15), you are probably blind.
The painting makes easy to see some abstract things.
4=1+1+2 and 9=1+1+2+2+3.
In fact, for any natural number n the corresponding square number
Therefore, you can easily see that the n-th square number is the sum of the n-th and (n-1)-th triangular numbers. Does this make my painting abstract or not?