Industrial designer Dani Clode's field of specialty is prosthetics. She designed this Third Thumb, which anyone can strap on and learn to use in minutes:

The design of it is quite clever, and more low-tech than you'd think. A small motor worn like a wristwatch drives the orange tendons that actuate the thumb:

There are no electrodes or implants. Instead, two pressure sensors, which wirelessly communicate with the motor, are placed beneath each of the user's big toes:

Applying pressure to the right toe draws the Third Thumb across the base of the palm, towards the base of the other thumb; the X-axis, if you like. Applying pressure to the left toe draws the thumb in the Y-axis, towards the pinky. By learning to modulate pressure with both toes simultaneously, users can draw the thumb between the two axes, offering a novel addition to manual dexterity.

Clode is hoping her invention will help not only amputees, but children born with upper limb differences. But she also points out that the Third Thumb could be handy for all people. I can't argue; I can think of lots of repair tasks that seemingly require three hands. Perhaps all that's really needed is a third thumb.

In the video below, you can see a wide range of people using the Third Thumb for practical applications. It's striking to see how quickly they pick up using it:

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Clode is the Head Designer at Cambridge University's Plasticity Lab, which seeks to "understand how we could use technology to increase hand functionality in able and disabled individuals at all ages." The Lab is run by professor and neuroscientist Tamar Makin, who points out that the wide demographic spread of test subjects seen in the footage above is purposeful.

"To ensure everyone will have the opportunity to participate and benefit from these exciting advances," says Makin, "we need to explicitly integrate and measure inclusivity during the earliest possible stages of the research and development process."

"Given the diversity of bodies, it's crucial that the design stage of wearable technology is as inclusive as possible," says Clode. "It's equally important that these devices are accessible and functional for a wide range of users. Additionally, they should be easy for people to learn and use quickly."

Makin, Clode and their team have published a research paper on their Third Thumb findings, called "Evaluating initial usability of a hand augmentation device across a large and diverse sample."