A team of researchers has discovered the most effective shape for a urinal that minimizes splashing, which could lead to significant water savings and better accessibility for users, including those with disabilities. The design, named "Nautilus," won the 2026 Ig Nobel Physics Prize and was developed by Zhao Pan’s team from the University of Waterloo in Canada after over a decade of research. Their findings, published in April 2025 in the journal PNAS Nexus, could influence the design of public restrooms in the future. The study found that a 30-degree angle between the incoming urine stream and the urinal wall is key to preventing splashing. When urine hits the wall directly (perpendicular), it has the highest chance of splashing. As the angle becomes shallower, the risk of splashing decreases. Below 30 degrees, the urine no longer splashes and instead flows smoothly down the wall. This discovery led the researchers to design a urinal with a surface that follows a logarithmic spiral, known as a Bernoulli or nautilus spiral, which maintains the 30-degree angle at every point. The "Nautilus" design features a low rim, making it accessible for people of all sizes, including those using wheelchairs. In addition, the researchers developed a second model called "Cornucopia," which is shaped like a horn and adapts to the natural parabolic path of urine due to gravity. This model uses numerical simulations to account for the complex physics involved, which cannot be solved through simple equations. To test their designs, the researchers built prototypes using foam covered in synthetic resin and compared them with two existing urinals: a standard American model and Marcel Duchamp’s famous "Fontaine," a repurposed urinal from the 1917 art movement. They measured splashing both visually and by weighing the liquid that splashed onto a sheet on the floor. The results showed that their scientific designs splashed only 1.4% as much as traditional urinals. If all 56 million public urinals in the U.S. were replaced with these new designs, the researchers estimate that 10 million liters of water could be saved daily for cleaning purposes.