Yes, really. The illusion is called the Jastrow illusion.

There are a few different theories for how the Jastrow effect works. But basically, your brain compares the two sides of the respective track pieces that are next to each other. So instead of comparing the right side of one piece to the right side of the other, it compares the right side of the left track to the left side of the right track, because those two sides are next to each other.