Inserting elements using "with" notation:

import streamlit as st

with st.container():
   st.write("This is inside the container")

   # You can call any Streamlit command, including custom components:
   st.bar_chart(np.random.randn(50, 3))

st.write("This is outside the container")

Inserting elements out of order:

import streamlit as st

container = st.container(border=True)
container.write("This is inside the container")
st.write("This is outside the container")

# Now insert some more in the container
container.write("This is inside too")

Using height to make a grid:

import streamlit as st

row1 = st.columns(3)
row2 = st.columns(3)

for col in row1 + row2:
    tile = col.container(height=120)
    tile.title(":balloon:")

Using height to create a scrolling container for long content:

import streamlit as st

long_text = "Lorem ipsum. " * 1000

with st.container(height=300):
    st.markdown(long_text)