Phish opened its four-night stay at the Sphere Thursday with a four-hour show that used the advanced technology in the $2.3 billion arena to deliver a show that even the band’s most ardent fans have never experienced before. The band uses custom visuals on the 160,000-square foot 16K-by-16K LED screen. Three-dimensional blue bars move and spin in time and grow to meet beams of light falling from the ceiling.