The Simple Optical Illusion That Makes an Image Look Like It's Drawing Itself

iStock
iStock

Artist James Nolan Gandy invents robot arms that sketch intricate mathematical shapes with pen and paper. When viewed in real time, the effect is impressive. But it becomes even more so when the videos are sped up in a timelapse. If you look closely in the video below, the illustration appears to materialize faster than the robot can put the design to paper. Gizmodo recently explained how the illusion works to make it look like parts of the sketch are forming before the machine has time to draw them.

The optical illusion isn’t an example of tricky image editing: It’s the result of something called the wagon wheel effect. You can observe this in a car wheel accelerating down the highway or in propeller blades lifting up a helicopter. If an object makes enough rotations per second, it can appear to slow down, move backwards, or even stand still.

This is especially apparent on film. Every “moving image” we see on a screen is an illusion caused by the brain filling in the gaps between a sequence of still images. In the case of the timelapse video below, the camera captured the right amount of images, in the right order, to depict the pen as moving more slowly than it did in real life. But unlike the pen, the drawing formed throughout the video isn't subject to the wagon-wheel effect, so it still appears to move at full speed. This difference makes it look like the sketch is drawing itself, no pen required.

Gandy frequently shares behind-the-scenes videos of his mechanical art on his Instagram page. You can check out some of his non-timelapse clips like the one below to better understand how his machines work, then visit his website to browse and purchase the art made by his 'bots.

And if you think his stuff is impressive, make sure to explore some of the incredible art robots have made in the past.

[h/t Gizmodo]

Amazon's Best Black Friday Deals: Tech, Video Games, Kitchen Appliances, Clothing, and More

Amazon
Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

Black Friday is finally here, and Amazon is offering great deals on kitchen appliances, tech, video games, and plenty more. We will keep updating this page as sales come in, but for now, here are the best Amazon Black Friday sales to check out.

Kitchen

Instant Pot/Amazon

- Instant Pot Duo Plus 9-in-115 Quart Electric Pressure Cooker; $90 (save $40)

- Keurig K-Cafe Special Edition; $190 (save $30)

- Ninja OS301 Foodi 10-in-1 Pressure Cooker and Air Fryer; $125 (save $75)

- Nespresso Vertuo Next Coffee and Espresso Machine by Breville; $120 (save $60)

- KitchenAid KSMSFTA Sifter with Scale Attachment; $95 (save $75)

- Keurig K-Mini Coffee Maker; $60 (save $20)

- Cuisinart Bread Maker; $80 (save $97)

- Anova Culinary Sous Vide Precision Cooker; $139 (save $60)

- Aicook Juicer Machine; $35 (save $15)

- JoyJolt Double Wall Insulated Espresso Mugs - Set of Two; $14 (save $10)

- Longzon Silicone Stretch Lids - Set of 14; $16 (save $11)

- HadinEEon Milk Frother; $37 (save $33)

Home Appliances

Roomba/Amazon

- iRobot Roomba 675 Robot Vacuum with Wi-Fi Connectivity; $179 (save $101)

- ASAKUKI 500ml Premium Essential Oil Diffuser; $22 (save $4)

- Facebook Portal Smart Video Calling 10 inch Touch Screen Display with Alexa; $129 (save $50)

- Bissell air320 Smart Air Purifier with HEPA and Carbon Filters; $280 (save $50)

- Oscillating Quiet Cooling Fan Tower; $59 (save $31)

- TaoTronics PTC 1500W Fast Quiet Heating Ceramic Tower; $55 (save $10)

- Vitamix 068051 FoodCycler 2 Liter Capacity; $300 (save $100)

- Ring Video Doorbell; $70 (save $30)

Video games

Sony

- Marvel's Spider-Man: Game of The Year Edition for PlayStation 4; $20 (save $20)

- The Legend of Zelda: Link's Awakening; $40 (save $20)

- Hyrule Warriors: Age of Calamity; $50 (save $10)

- Marvel's Avengers; $25 (save $33)

- The Last of Us Part II for PlayStation 4; $30 (save $30)

- LEGO Harry Potter: Collection; $15 (save $15)

- Ghost of Tsushima; $40 (save $20)

- BioShock: The Collection; $20 (save $30)

- The Sims 4; $24 (save $20)

- God of Warfor PlayStation 4; $10 (save $10)

- Days Gonefor PlayStation 4; $20 (save $6)

- Luigi's Mansion 3 for Nintendo Switch; $40 (save $20)

Computers and tablets

Microsoft/Amazon

- New Apple MacBook Pro 16 inches with 512 GB; $2149 (save $250)

- Microsoft Surface Laptop 3 with 13.5 inch Touch-Screen; $1200 (save $400)

- Lenovo ThinkPad T490 Laptop; $889 (save $111)

- Amazon Fire HD 10 Tablet (64GB); $120 (save $70)

- Amazon Fire HD 10 Kids Edition Tablet (32 GB); $130 (save $70)

- Apple iPad Mini (64 GB); $335 (save $64)

- Vankyo MatrixPad S2 Tablet; $120 (save $10)

Tech, gadgets, and TVs

Apple/Amazon

- Apple Watch Series 3 with GPS; $120 (save $79)

- Seneo Wireless Charger, 3 in 1 Wireless Charging Station; $16 (save $10)

- SAMSUNG 75-inch Class Crystal 4K Smart TV; $998 (save $200)

- Nixplay 2K Smart Digital Picture Frame 9.7 Inch Silver; $238 (save $92)

- All-New Amazon Echo Dot with Clock and Alexa (4th Gen); $39 (save $21)

- MACTREM LED Ring Light 6" with Tripod Stand; $16 (save $3)

- Amazon Fire TV Stick with Alexa Voice Remote; $28 (save $12)

- DR. J Professional HI-04 Mini Projector; $93 (save $37)

Headphones and speakers

Beats/Amazon

- Beats Solo3 Wireless On-Ear Headphones; $120 (Save $80)

- Apple AirPods Pro; $169 (save $50)

- Anker Soundcore Upgraded Bluetooth Speaker; $22 (save $8)

- Powerbeats Pro Wireless Earphones; $175 (save $75)

- JBL Boombox; $280 (save $120)

Movies and TV

HBO/Amazon

- Game of Thrones: The Complete Series; $115 (save $89)

- Jurassic World 5-Movie Set; $23 (save $37)

- Deadwood: The Complete Series; $42 (save $28)

- Back to the Future Trilogy; $15 (save $21)

Toys and Games

Amazon

- Awkward Family Photos Greatest Hits; $15 (save $10)

- Exploding Kittens Card Game; $10 (save $10)

- Cards Against Humanity: Hidden Gems Bundle; $14 (save $5)

- LOL Surprise OMG Remix Pop B.B. Fashion Doll; $29 (save $6)

- LEGO Ideas Ship in a Bottle 92177 Expert Building Kit; $56 (save $14)

Furniture

Casper/Amazon

- Casper Sleep Element Queen Mattress; $476 (save $119)

- ZINUS Alexis Deluxe Wood Platform Bed Frame; $135 (save $24)

- ROMOON Dresser Organizer with 5 Drawers; $59 (save $11) 

- AmazonBasics Room Darkening Blackout Window Curtains; $26 (save $5)

- Writing Desk by Caffoz; $119 (save $21)

- SPACE Seating Office Support Managers Chair; $112 (save $116)

- Rivet Globe Stick Table Lamp; $53 (save $17)

- Christopher Knight Home Merel Mid-Century Modern Club Chair; $188 (save $10)

- Walker Edison Furniture Industrial Rectangular Coffee Table; $121 (save $48)

Beauty

Haus/Amazon

- MySmile Teeth Whitening Kit with LED Light; $21 (save $12) 

- Cliganic USDA Organic Lip Balms Set of Six; $6 (save $4)

- HAUS LABORATORIES By Lady Gaga: LE RIOT LIP GLOSS; $7 (save $11)

- Native Deodorant for Men and Women Set of Three; $25 (save $11) 

- BAIMEI Rose Quartz Jade Roller & Gua Sha; $14 (save $3)

- Honest Beauty Clearing Night Serum with Pure Retinol and Salicylic Acid; $20 (save $8)

- WOW Apple Cider Vinegar Shampoo and Hair Conditioner Set; $30 (save $5) 

- La Roche-Posay Effaclar Purifying Foaming Gel Cleanser; $15 (save $5)

- wet n wild Bretman Rock Shadow Palette; $9 (save $6)

- EltaMD UV Daily Tinted Face Sunscreen Moisturizer with Hyaluronic Acid; $25 (save $6)

Clothes

Ganni/Amazon

- Ganni Women's Crispy Jacquard Dress; $200 (save $86) 

- The Drop Women's Maya Silky Slip Skirt; $36 (save $9)

- Steve Madden Women's Editor Boot; $80 (save $30)

- adidas Women's Roguera Cross Trainer; $40 (save $25)

- Line & Dot Women's Elizabeth Sweater; $74 (save $18)

- Levi's Men's Sherpa Trucker Jacket; $57 (save $41)

- Adidas Men's Essentials 3-Stripes Tapered Training Joggers Sweatpants; $28 (save $12)

- Timex Men's Weekender XL 43mm Watch; $32 (save $20)

- Ray-Ban Unisex-Adult Hexagonal Flat Lenses Sunglasses; $108 (save $46) 

- Reebok Men's Flashfilm Train Cross Trainer; $64 (save $16)

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New Online Art Exhibition Needs the Public’s Help to Track Down Lost Masterpieces by Van Gogh, Monet, and More

Vincent van Gogh's original Portrait of Dr. Gachet wasn't stolen, but it hasn't been seen in 30 years.
Vincent van Gogh's original Portrait of Dr. Gachet wasn't stolen, but it hasn't been seen in 30 years.
Vincent van Gogh, Wikimedia Commons // Public Domain

If you wanted to compare both versions of Vincent van Gogh’s Portrait of Dr. Gachet in person, you couldn’t. While the second one currently hangs in Paris’s Musée d'Orsay, the public hasn’t seen the original painting since 1990. In fact, nobody’s really sure where it is—after its owner Ryoei Saito died in 1996, the precious item passed from private collector to private collector, but the identity of its current owner is shrouded in mystery.

As Smithsonian Magazine reports, Portrait of Dr. Gachet (1890) is one of a dozen paintings in “Missing Masterpieces,” a digital exhibit of some of the world’s most famous lost artworks. It’s not the only Van Gogh in the collection. His 1884 painting The Parsonage Garden at Nuenen in Spring was snatched from the Netherlands’ Singer Laren museum earlier this year; and his 1888 painting The Painter on His Way to Work has been missing since World War II. Other works include View of Auvers-sur-Oise by Paul Cézanne, William Blake’s Last Judgement, and two bridge paintings by Claude Monet.

Paul Cézanne's View of Auvers-sur-Oise was stolen from the University of Oxford's art museum on New Year's Eve in 1999.Ashmolean Museum, Wikimedia Commons // Public Domain

The new online exhibit is a collaboration between Samsung and art crime expert Noah Charney, who founded The Association for Research into Crimes Against Art. It isn’t just a page where art enthusiasts can explore the stories behind the missing works—it’s also a way to encourage people to come forward with information that could lead to the recovery of the works themselves.

“From contradictory media reports to speculation in Reddit feeds—the clues are out there, but the volume of information can be overwhelming,” Charney said in a press release. “This is where technology and social media can help by bringing people together to assist the search. It’s not unheard of for an innocuous tip posted online to be the key that unlocks a case.”

The exhibition will be online through February 10, 2021, and citizen sleuths can email their tips to missingmasterpieces@artcrimeresearch.org.

[h/t Smithsonian Magazine]