SAN JOSE, Calif. (AP) — Twice as fast as an airplane, cheaper than a bullet train and completely self-powered: that's the mysterious transportation system that inventor and entrepreneur Elon Musk is promising to reveal design plans for Monday.

Musk has been dropping hints about his "Hyperloop" system for more than a year during public events, mentioning that it could never crash, would be immune to weather and would move people from Los Angeles to San Francisco in half an hour.

Coming from almost anyone else, the hyperbole would be hard to take seriously. But billionaire Musk — who sold his first computer program, a $500 space game called Blastar, at age 12 — has earned his reputation as an inventor and entrepreneur, co-founding online payment firm PayPal, electric luxury carmaker Tesla Motors Inc. and rocket-building company SpaceX.

During a Tesla earnings call Thursday, Musk said he would reveal plans for the Hyperloop on Monday. But he said he is too focused on other projects to consider actually building it.

"I think I kind of shot myself by ever mentioning the Hyperloop," he said. "I don't have any plans to execute, because I must remain focused on SpaceX and Tesla."

He said he would fulfill his commitment to publishing a design, and he said he invites critical feedback after its release Monday to "see if the people can find ways to improve it." It will be an open-source design, meaning anyone can use it and modify it.

Also Thursday, Musk said during a Google Hangout with Sir Richard Branson about entrepreneurship, "It does involve a tube, but not a vacuum tube."

His hints and promises have prompted a flurry of online speculation.

Canadian John Gardi, a self-described "tinkerer," posted online and tweeted his conjecture a few weeks ago to Musk.

"I believe that Hyperloop is merely a modern day version of the pneumatic tubes used in banks, stores, and industry to move money and small items over long distances or to other floors of a building," he said.

Musk responded, "Your guess is the closest I've seen anyone guess so far."

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  • Corning's 'A Day Made of Glass...'

    Corning makes the super-strong "Gorilla Glass" that might cover your smartphone's touchscreen. (The company's customers include Samsung, Dell, Sony and LG). No wonder, then, that the glass manufacturer's vision of the future involves a lot of glass, and a lot of touchscreens on that glass. All touchscreens everywhere, shouts Corning! We shout: "Cool!"

  • Nokia Kinetic Device

    Though <a href="http://events.nokia.com/nokiaworld/" target="_hplink">the Nokia World 2011 Conference</a> was held to <a href="http://www.huffingtonpost.com/2011/10/26/nokia-lumia-800-videos_n_1032335.html" target="_hplink">announce the Finnish handset-maker's new Windows Phones</a>, a lot of the conversation from bloggers centered on Nokia's Kinetic Device, a prototype of a smartphone that was operated by bending and twisting (rather than pinching-to-zoom, which dominates today). <a href="http://www.engadget.com/2011/10/30/samsung-to-offer-flexible-displays-in-2012-challenges-nokia-to/" target="_hplink">Samsung recently announced</a> that it is preparing to release flexible devices in 2012; so, if you're in the market for a smartphone, get ready to twist again, like we will next year. Worth watching, if only to hear the adorable Nokia engineer proclaim, "I'M FROM FINLAND, AND WE HAVE LONG, CHILLY WINTER."

  • Roll-Out Laptop

    While we wish this video had been <a href="http://youtubedoubler.com/?video1=http%3A%2F%2Fwww.youtube.com%2Fwatch?feature%3Dplayer_embedded%26v%3Db3txQs7jEJ4&start1=&video2=http%3A%2F%2Fwww.youtube.com%2Fwatch?v%3D3ArhZPYplFk&start2=&authorName=gilbertjasono" target="_hplink">synced up with a certain unforgettable Ludacris single</a>, this concept laptop can roll out like paper towels, power supply and all.

  • Nokia HumanForm

    After showing off that Kinetic Device at Nokia World 2011, Nokia <a href="http://www.huffingtonpost.com/2011/11/10/nokia-humanform-future-smartphone-video_n_1086517.html" target="_hplink">followed up with this thought-piece</a> of a video, which displayed a graphically-rendered futuristic smartphone called "HumanForm." Like the Kinetic Device, it emphasizes bends, twists and touch buttons all over the place (on the front, on the side, on the back -- <em>everywhere</em>).

  • Microsoft's 3D HoloDesk

    This video has no sound, but it doesn't really need any: Just LOOK at what's going on inside Microsoft's prototype HoloDesk, which, besides being a great tool to practice juggling, also looks like a neat way to learn physics and work on on tactile projects with remote collaborators.

  • Paper-Thin Concept Smartphone

    In May we got a glimpse of this paper-thin concept smartphone, which through the use of bending and a nifty printed circuit board was able to act simultaneously as mp3 player, cell phone and, with its thinness, bookmark.

  • Vision Of The Future From 3M

    3M's vision of the future includes a flexible and transparent gaming device, a really cool-looking washing machine and even a Connect Four made of clear glass. No, don't drop that red piece there! Ah, shoot. Too late.

  • OmniTouch With Touchscreens On Any Surface

    Using technology from the Kinect gaming system, a research team made of developers from Microsoft and Carnegie-Mellon University revealed in October that they've come up with a system that can turn virtually any surface into a touchscreen. <a href="http://www.technologyreview.com/computing/38933/" target="_hplink">Per MIT's Technology Review</a>: <blockquote>OmniTouch works by bringing together a miniature projector and an infrared depth camera, similar to the kind used in Microsoft's Kinect game console, to create a shoulder-worn system designed to interface with mobile devices such as smart phones</blockquote>

  • Smartphone With Pico Projector

    This one is a little more imminent and much more realistic, as it actually exists. Check out this smartphone rigged up with a pico projector that puts your Android or iOS interface on any surface you please. Right now the thing is a little bulky to jam into your jeans pocket (especially if you're wearing skinny jeans) but <a href="http://www.huffingtonpost.com/2011/08/18/apple-patents-concepts-designs_n_925401.html#s328317&title=3D_Holographic_Projector" target="_hplink">if Apple's 2006 patent proves fruitful</a>, this one could be right around the corner.

  • Microsoft Future Vision

    Microsoft is not shy about releasing its vision of a techie future, and this Future Vision might be its most grandiloquent statement yet. Behold this seamlessly edited look at how the company envisions its products to evolve in the office, in the home and on the go. <em>Minority Report</em> comparisons abound. I, for one, can't wait to get my multilingual eyeglasses.

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