Examples
When we draw a dice 5000 times, we expect to get each value around 1000 times.
But when we draw two dices and sum the result, the distribution is going to be quite different.
A histogram illustrates those distributions:

import numpy as np
import pandas as pd

df = pd.DataFrame(
    np.random.randint(2, 8, 5000),
    columns = ['one'])
df['two'] = df['one'] + np.random.randint(2, 8, 5000)
ax = df.plot.hist(bins=12, alpha=0.5)