What would it take to simulate the sensorium of a single person on any given day and channel it into my own nervous system? Something like the SimStim technology in William Gibson’s 1984 novel Neuromancer, or the apparatuses that simulate the sensory experience of other people inhabiting other worlds in the Wachowskis’ 1999 film The Matrix. What if a machine were trained to create new 3D spaces based on photographs and videos: could it then simulate a world indistinguishable from our own? Science-fiction fantasies and ethical questions such as these come easily when considering Casey Reas’s work. This has less to do with the images he creates than how he creates them. Reas is best known for co-developing Processing, an open-source software and coding language intended to make computer programming easier for non-programmer artists and designers. By turns poignant and unnerving, his exhibition “Alchemical” at New York’s bitforms showcases still images and videos made using generative adversarial networks (GANs), a machine-learning program that creates new images from processing thousands of existing ones. The images are accompanied by glitchy, hypnotic music composed by Jan St. Werner, one half of the electronic music duo Mouse on Mars. In the first room …