# https://altair-viz.github.io/gallery/filled_step_chart.html

import altair as alt
from vega_datasets import data

source = data.stocks()

alt.Chart(source).mark_area(
    color="lightblue", interpolate="step-after", line=True
).encode(x="date", y="price").transform_filter(alt.datum.symbol == "GOOG")
