Of the many uncertainties this election, one thing was fairly predictable: President Donald Trump would look like he was coasting to victory in Pennsylvania on election night, but then there would be what’s known as a “blue shift” toward Joe Biden as votes were counted in the hours and days afterward.

It was the direct outcome of three simple facts:

  • Pennsylvania has way more mail ballots than ever before.

  • Counting those mail ballots takes a long time.

  • Democrats are much more likely to vote by mail than Republicans are.

It’s not fraud, it’s not the election being stolen. It’s just the natural product of the way votes are counted.

As we noted, first in January, many times since, and then again before polls ever closed Tuesday:

After polls close at 8 p.m. in Pennsylvania, the first results that come in could make it look as if former Vice President Joe Biden is winning in a landslide. But then the numbers could start to shift, and by the end of the night, President Donald Trump could look as if he’s the one winning big. Then, in the days afterward, vote tallies could slowly turn back in Biden’s favor.

» READ MORE: The ‘blue shift’ is already moving vote margins in the Philly suburbs from Trump to Biden

That’s exactly what’s happened — and is happening now. It’s visualized in the chart below, which shows the unofficial vote totals for Biden and Trump as the Associated Press reported them since polls closed at 8 p.m. Tuesday, and as they continue to change. The red line is Trump’s vote total in Pennsylvania. The blue line is Biden’s vote total in Pennsylvania. The dotted red line represents Trump’s 2016 vote total.

This is what “the blue shift” actually looks like.