The triangles are touch sensitive, “Just press each piece and various colors will be gradated”.
The team have shared the instructions and design files to make the 6 part version on Instructables. It uses an Arduino Mega to control the Neopixel LEDs and the casings are made from laser cut acrylic and 3D printed PLA. They added a light diffusion film on the acrylic fronts to improve the light quality.
Instructions are available here.