Model Challenge Submission Deadline Extended

The deadline for model challenge submissions is now changed to Friday June 17 (21:00 UTC).

We hope that this extension will be helpful to all of our challengers.

In addition, please be aware that indicated symmetry centers in the model challenge guide may not be exact. 
This issue was just raised by one participant—we are investigating and will send a further update about this soon.

Further note (4/28): symmetry issue has been resolved