The scatterplot matrix, known acronymically as SPLOM, is a relatively uncommon graphical tool that uses multiple scatterplots to determine the correlation (if any) between a series of variables.
These scatterplots are then organized into a matrix, making it easy to look at all the potential correlations in one place.

This dataset examines sepal length, sepal width, petal length, and petal width and then classifies the species.

Light blue indicates Iris setosa, pink Iris versicolor, and purple Iris virginica.

Iris setosa has a large sepal width but small petal width.
Iris virginica has a large sepal length and petal length.
Iris versicolor sits between setosa and virginica much of the time.