Shown is the result of the sandpile on the square lattice starting from 2³⁰ chips at the origin.

Zoom by clicking or using your mouse scrollwheel, and click and drag to move the image. If you zoom all the way in, look for various periodic patterns produced by the sandpile.

Click on "Fewer chips" many times to see how the pile looks when started from a more modest number of chips. Then see how things change as the number of chips increases...