Online registration is closed for this event. If available, tickets on the day of the event may incur an additional charge.

Math Encounters — Online:

"Bouncing Billiards: The Symmetries and Mathematics in the Path of a Rolling Ball" with Diana Davis

Wednesday, February 3 at 4:00 pm ET (New York)

If you hit a ball on a pool table, it will bounce around for a while — it might even return to where it started and repeat its path.  It turns out that these periodic trajectories are very beautiful, forming a unique kind of mathematical art.  Join Dr. Diana Davis, Phillips Exeter Academy Instructor in Mathematics, as she shares an amazing array of images, discusses how she and her colleagues figured out how to draw these intricate paths, and reveals some surprising properties — buddies, families, and symmetry — that they discovered along the way.

Special introduction by Amie Wilkinson, Professor of Mathematics, University of Chicago.

Purchase "math is beautiful" earrings created by Diana at Additions, the shop at MoMath.

To fully participate, have the following handy:

  • Paper
  • Pencil
  • A digital or printed copy of the handout that will be emailed to registrants

This is a live-streamed event.  Occasional video recordings are made available for a fee at

This page is for the 4:00 pm ET (New York) session.  Click here to register for the 7:00 pm ET (New York) session instead.

By registering for a Math Encounters presentation, you agree that you may be photographed or videotaped by Museum staff and associates.

Math Encounters is MoMath's popular free public presentation series celebrating the spectacular world of mathematics, produced with support from the Simons Foundation.

For further information, call the National Museum of Mathematics at 212-542-0566 or email

Please check our online shop for books by Math Encounters presenters.

February 3rd, 2021 from  4:00 pm to  5:30 pm
MoMath Online
United States