The “Celebration of Mind” is held annually on or around Martin Gardner’s birthday (October 21st). This year, the 10th annual CoM is being held virtually all week long, with Zoom webinars at noon, 4pm, and 8pm daily from Saturday 2020-10-17 until Friday 2020-10-23.

The annual October “Celebration of Mind” is not to be confused with the March/April “Gathering 4 Gardner” held biennially since G4G2 in 1996. I admit I have only just learned that these are different!

I just attended Scott Kim’s webinar on “Musical Illusions,” in which he demonstrated how to play the Shepard tone on the piano, and also how one person can harmonize “Frère Jacques” by simultaneously humming one part and whistling another. (This was quite impressive. I may be playing a bit of telephone here, but my understanding is that Kim basically taught himself to hum-whistle in 24 hours after Douglas Hofstadter dared him to.) Incidentally, this same pair of parlor tricks is mentioned in a footnote to Musical Illusions and Phantom Words (2019), by Diana Deutsch, who was also in the webinar audience.

For more Shepard-tone craziness, check out this animation by Vladimir Bulatov (video) and Daniel Repasky (audio).

Scott Kim is also known for creating “ambigrams,” as in his 1981 book Inversions. For the first four “Celebration of Mind” events, in 2010, 2011, 2012, and 2013, Kim created amazing invertible designs. Hover or tap to rotate each image:

Scott Kim also created an invertible logo for the eighth biennial “Gathering for Gardner” (2008):

Images from martin-gardner.org and Butler University.