But in one sense this is actually 2 shapes that are mirror images. It's still really cool, but I don't think it is ultimately what we've been looking for. As proof that it's not, we all know that a paper presenting one that doesn't need its mirror image to tile the plane aperiodically would still be a big dea.
It's not really a single shape since the tiling contains the shape's reflection which is normally considered a different shape since its handedness changes.
...they found a single shape
Kind of, though, right? One could also look at it as they've found two shapes that happen to be reflections of each other.