Correction to: Nature https://doi.org/10.1038/s41586-019-1141-3, published online 24 April 2019.

In Fig. 1 of this Letter, owing to an error in the production process, the rotation signs around 90°, 135° and 15° were inadvertently missing. In addition, in the HTML version of the Letter, Extended Data Tables 2 and 3 showed the wrong tables (these were correct in the PDF). These errors have been corrected online.