Answer to my most commonly asked questions:

1) Yes, I am Cliff Stoll, and I make and sell Klein bottles. My business is named Acme Klein Bottle.

2) Yes, I regularly send these to countries around the world.

3) Yes, you can safely order from this website, and I will send your Klein bottle within 24 hours.

4) Yes, I pack each one very securely to survive the post; I guarantee safe, speedy delivery.

5) If you are unhappy with your Klein bottle, I will refund your money.

6) If this is a gift, I'll print "Happy Birthday" (or whatever you want) on the packing slip or the outside of the package. If you wish, I'll write your message on the bottle with a Sharpie pen.

7) No, I no longer do the hot glass work - I contract this out to professional glassblowing shops. I do everything else myself - from design to packing to writing the html on this website, with occasional help from my son Danny, my daughter Zoe, and my wife Pat.

8) Yes, you are welcome to visit if you are traveling to Northern California (San Francisco/Oakland/Berkeley) Call first - 510 654 3958

9) No, I cannot engrave these glass Klein bottles. The borosilicate glass laughs at laser beams and the compound curves defy X-Y tables..

10) Yes, there are many math jokes on this website, but despite that, I really do sell Klein bottles

11) Yes, my son Danny and I designed each of these bottles ourselves. Our designs are copyright © by Cliff Stoll

12) My website looks old-fashioned because it loads faster this way and (mainly) I'm too lazy to rewrite it. I wrote much of it between 1996 to 1999 (before CSS was invented), I last updated this on a bright Sunday afternoon in Oakland, 2025 January 26.

13) Yes, that's me in the [ video / book / talk / college / bowling alley / quilt guild ]

-Cliff Stoll in Oakland (two blocks from Berkeley, 10 km east of San Francisco, and epsilon away from some boundary)

ARE YOU A STUDENT, AGE 12 TO 17? Do you like the kind of math humor that's on this website? Then consider one of the terrific summer math camps! Several that come to mind: the Hampshire Summer Studies in Math (in Amherst, Massachusetts during July & August... learn why the Yellow Pig endorses 17 varieties of Acme Klein bottles -- hcssim.org). Also, the MathILy program at Bryn Mawr (five weeks of maximum mathematical marvelousness) (www.mathily.org). I've also heard great things about Epsilon Camp in Utah (well, one of the Epsilon camp counselors visited, and she really impressed me![Hi Nina!]) There are dozens more camps-- see a list of these camps at www.ams.org/programs/students/emp-mathcamps ... feel free to ask me for opinions or comments about these various math camps. Also -- Math Circles are springing up around the world ... find out if there's one in your neighborhood: www.mathcircles.org/Wiki_ExistingMathCirclePrograms_view

In response to almost two requests, I've uploaded my IMPERFECTO RULER

Our "M&M's in a Klein bottle Contest" is closed

When you order from this website, your should immediately receive an automated confirmation from my system. When I actually pack your Klein bottle, I will compose a non-automated email, with the return address of kleinbottle aaattat@attt kleinbottle ddoatatdot com. That second email will have a tracking number in it, as well as a link to photos of the package that I'm sending to you. If you don't see that second email within a day of ordering, please check your spam/junk mail folder. And if you still don't see that email from me, please send me a note and I'll figure out what's worng.

My email troubles: I receive huge amounts of spam. I never send out any spam. If you write to me, I may not see your email unless you include the phrase "klein bottle" in the subject. My replies to your may end up in your spam folder, so please include my address in your list of Permitted Senders.

HOW TO GET EMAIL TO CLIFF: Send me email - KLEINBOTTLE aa ttt KLEINBOTTLE (ddoott] COM Important: to get through layers of my spam filters, please include the two words "Klein Bottle" in the subject of your email and also in the body of your text. Please use plain text without html. Email with subjects like "Hello Cliff"or "Do you ship to Nigeria?"or "Good Day" or "HI"will be delayed until I look at my spam folder.

HOW TO RECEIVE EMAIL FROM CLIFF: If you purchase anything from me, or write to me, please add kleinbottle aa ttt kleinbottle (ddooott) com to your Permitted Senders. This is especially important if you use gmail, hotmail, yahoo, or AOL. Much of my email to these mailboxes gets blocked as spam, which annoys me greatly, especially when I spend half an hour composing an email and it winds up in the gutter.

Acme Klein Bottle -- by Cliff Stoll, (and Pat, Zoey, & Danny Stoll) 6270 Colby St., Oakland, California, 94618 USA phone +1 510 654 3958 We are a family business, operating from our home. You're welcome to stop by for coffee & chat - please call ahead if you plan to visit.

** * * UPCOMING TRAVEL: * * **

When I'm home, I send out Klein bottles as I receive orders - within 24 hours, and often within the hour. When I travel, I send out all Klein bottles when I return. Here's my travel schedule: 

Traveling May 28 to June 9, 2025; I'll be at Chicago Thotcon on May 29 & 30