The journey to cruelty-free circus acts began in 2020 not with a bang or clashing cymbals but with the whisper of discovery over centuries, and the curiosity of light. Around 500 B.C., Pythagoras said light emanated from a luminous object to the eye. Two hundred years later, Aristotle believed light was indefinable and not worth serious contemplation. Ptolemy discovered the process of light refraction circa 130 A.D., and a thousand years later, Arab mathematician Alhazen introduced the concept of a light ray. Just before his death in 1673, French priest Ignace-Gaston Pardies published his manuscript Traité complet d’Optique (Complete Optical Treatise), in which he proposed the first notions of wave theory. In 1678, Dutch physicist Christiaan Huygens proposed his own wave theory to the Paris Académie des sciences, which was published in 1690 as Traité de la lumière, or Treatise on Light. A life-size rendering of an African elephant projected on a thin veil known as a scrim. Courtesy of Flickr/Roncalli Circus/CC In 1801, Thomas Young resurrected Huygens’ century-old wave theory, becoming the first to demonstrate that light added to light can produce darkness, a phenomenon known as interference. Then in 1971, Dennis Gabor delivered his Nobel lecture on holography, detailing the electron microscope he used to create an interference pattern he would later call a hologram. (He also credited Young.) On Easter Sunday in 1947, Gabor began steps toward improving the electron microscope and developing his theory of using reconstructed wavefronts. He used the microscope to produce interference between an object beam and the coherent background of negative photographs. Gabor called this interference pattern a hologram, from the Greek word holos, meaning “the whole,” because the photograph contained the whole information. “The hologram was then reconstructed with light,” Gabor said, “in an optical system which corrected the aberrations of the electron optics.” Today, the term hologram has been popularized and woven into the lexicon. And, as reports came in (in December) that Circus Roncalli’s founder and director, Bernhard Paul, had swapped out live animal acts for dancing holographic images, the word hologram was used colloquially. According to Dan Novy of MIT’s Media Lab, Paul’s animals are projections that rely on a material called scrims. Scrims create a floating 2D illusion via projectors and semitransparent, loose-weave material. The projections lack two distinguishing factors of true holograms: parallax and accommodation. While the light-based simulacrums capture the look of the animals, an accurate description lies in the uncanny valley between science and consumerism. Daniel Smalley, a Brigham Young University professor of electrical and computer engineering who uses lasers to create 3D volumetric images, said it isn’t important whether the circus uses real holograms, projections, or even Pepper’s ghost, the optical illusion popularized by John Henry Pepper. The projected images are mesmerizing, and they are a move forward in the elimination of animal cruelty in circus acts.