A lag plot is a special type of scatter plot with variables (X, X-lagged, and so on).

X -lagged is the variable that's derived from X with a time lag. The graph is plotted among two variables and the plot is used to determine the randomness, model suitability, outliers, and serial correlation in the data – especially time series data:

s = pd.Series(np.random.uniform(size=100)) 

This results in the following output: