NOT TODAY, EBAY (34)
By:
April 16, 2026
One in a series of posts via which Josh Glenn will share recent examples of stuff that he was tempted to purchase via eBay… but, heroically, didn’t.
Topology Joke Mug 30cm Diameter – Funny Math Coffee Cup with Donut and Coffee
C $49.00
I think it’s rather misleading to describe this 3-D printed object lesson — a useable coffee mug, along with its various topological deformations resulting in a torus/doughnut — as “funny,” but I do find it charming and wry.
Topology, of course, is the branch of mathematics concerned with the properties of a geometric object that are preserved under continuous deformations, such as stretching, twisting, crumpling, and bending; that is, without closing holes, opening holes, tearing, gluing, or passing through itself. One hears there’s a joke among mathematicians in which a topologist cannot distinguish a coffee mug from a doughnut.
Further research suggests that this 3D printed object replicates a ceramic model created by the British-American mathematician Henry Segerman, who does research in three-dimensional geometry and topology, and who is a pioneer in using 3-D printing to illustrate topological marvels.
I’ve also seen coffee mugs imprinted with witticisms like, “This is a donut. Topologically speaking.” Now that’s funny.
MORE FURSHLUGGINER THEORIES BY JOSH GLENN: SCHEMATIZING | IN CAHOOTS | JOSH’S MIDJOURNEY | POPSZTÁR SAMIZDAT | VIRUS VIGILANTE | TAKING THE MICKEY | WE ARE IRON MAN | AND WE LIVED BENEATH THE WAVES | IS IT A CHAMBER POT? | I’D LIKE TO FORCE THE WORLD TO SING | THE ARGONAUT FOLLY | THE PERFECT FLANEUR | THE TWENTIETH DAY OF JANUARY | THE REAL THING | THE YHWH VIRUS | THE SWEETEST HANGOVER | THE ORIGINAL STOOGE | BACK TO UTOPIA | FAKE AUTHENTICITY | CAMP, KITSCH & CHEESE | THE UNCLE HYPOTHESIS | MEET THE SEMIONAUTS | THE ABDUCTIVE METHOD | ORIGIN OF THE POGO | THE BLACK IRON PRISON | BLUE KRISHMA | BIG MAL LIVES | SCHMOOZITSU | YOU DOWN WITH VCP? | CALVIN PEEING MEME | DANIEL CLOWES: AGAINST GROOVY | DEBATING IN A VACUUM | PLUPERFECT PDA | SHOCKING BLOCKING.