If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.


Science Communication


Cool cats in fake squares and hands that tell chemical stories

by Megha Satyanarayana
June 13, 2021 | A version of this story appeared in Volume 99, Issue 22


Cat-aloging feline behavior

Credit: Tara McCready
Feline fits: Ash, like many cats, sees the lines of a square where they don't exist and sits in the middle.

Cats love squares. Any cat lover can verify the feline phenomenon of sitting in square things, whether they’re boxes (thank you, Schrödinger), suitcases, or even square shapes made of tape. Gabriella Smith knows this kitty-sitting behavior well: the animal-behavior scientist says research suggests that cats do this because they like the pressure provided by an enclosed space, or as ambush hunters, they like hiding in small spaces before a predatory pounce. But that doesn’t quite explain cats’ tendency to plop themselves inside taped squares on the floor. While Smith was a master’s degree student at Hunter College, she attended a lecture about how dogs perceive illusions, and she wondered how cats might perceive illusions as well.

A cat sits in a Kanizsa square.
Credit: Gabriella Smith
Kitty cornered: Gabriella Smith studies how cats, like her cat Pancetta, see boxes where there are only corners and then sit in them.

To test the idea, she turned to something called a Kanizsa square, a series of Pac-Man-like circles that, when lined up properly, create the illusion of a square between them. Taking advantage of the Twitter hashtag #CatSquare, Smith asked cat owners to print the Kanizsa squares, place them on the floor, and watch as the cats descended. Thirty people completed the 6-day observation with their cats. Nine of those cats selected the illusion about as often as an actual tape square on the ground, suggesting that these kitties saw a square that wasn’t there about as often as they saw the real thing (Appl. Anim. Behav. Sci. 2021, DOI: 10.1016/j.applanim.2021.105338).

“It’s a very kind of ancient ability, and it likely derived from attention to contours,” Smith says, explaining that the ability to perceive illusions is conserved in animals like fish and mammals and that the Kanizsa square emerges in our minds because of a difference in light intensity between the corners and the open space. “Our brain wants to continue that contour. This is likely a primordial sensitivity: you don’t want to fall into a hole; you don’t want to fall off a cliff. Attention to contours is likely very evolutionarily important.”

Smith says this citizen science effort should be repeated in a more controlled setting, but it opens the door to research on how cats see the world around them and how they perceive both dimensions and boundaries. But for meow, Smith is happy to snuggle with her feline friend, Pancetta, and watch as the kitty kneads blankets, chirps at birds, and does all the weird things that make felines fascinating.


The art of electrochemistry

Hands with henna designs inspired by science.
Credit: Safia Jilani
Digital design: Safia Jilani's science-inspired henna art has earned her fans around the globe.

Mehndi is a traditional practice in South Asia whereby designs are drawn on skin using henna paste. This use of henna has religious and cultural significance for South Asians of many religions. Safia Jilani, a graduate student in chemistry at Georgetown University who is of South Asian descent, has been working with henna for several years and decided to infuse her love of chemistry into henna art that she applies to her own hands.

Her most recent designs celebrate Eid al-Fitr, which marks the end of Ramadan, an important period of fasting, prayer, and reflection for Muslims worldwide. She tells Newscripts that her hands tell a story, and this one is of her work as a mentor to younger chemistry students. Her design illustrates reactions that helped those students create nanoparticles. It also features what she says is the most important reaction to her doctoral degree: the electrochemical interaction of ethanol and oxygen to make carbon dioxide. In addition, she includes the Gibbs free-energy equation as the hallmark of each of her designs. Jilani says that her hands are “like an expression of joy, and I express that celebration and joy through science.” Can you recognize all the chemistry on her hands? This Newscriptster is a biology major, so help a girl out, will ya?

Please send comments and suggestions to


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.