Dancers these days are enjoying an ever-enlarging toy box of intriguing digital playthings as designers develop sensors that can be embedded in pointe shoes, clipped to tunics, implanted in headgear, and tucked up tutus. These allow performers to interact with software, trigger lights and sound, create computer-screen calligraphies, and more. Chinese researchers imagine a classroom application. They claim that sensors in dance shoes can determine whether the dancer’s technique is up to standard—relieving teachers of this chore. Choreographers and software designers are flooding stages with digital projections, making them look like 3-D computer screens. Swirling, pulsing virtual environments surround performers in works like those from dance company Chunky Move in Australia, Japanese dancer Yoko Ando, and digital artists Adrien M/Claire B in France.