LONDON — Patrick Cox is a shoe designer again, something he said with equal parts surprise and satisfaction at the four-day pop-up of his Ibiza-based, psychedelics- and mental health-focused brand Doors of Perception in his former London neighborhood of Notting Hill. “There’s a saying, life is in two acts. It’s about surviving the intermission. I got kind of stuck on the intermission for about a decade,” said Cox, who left his namesake brand in 2007 after more than two decades with 200 employees and 10 stores worldwide at its peak. The end of that chapter, he admitted, was “all very sad” and felt like “unfinished business.” You May Also Like “My teacher at the time said the only way you’re truly going to be happy is if you reconnect with your creativity. He’d seen that if people talked about shoes or fashion, I’d get up and walk out of the room. I had to make peace with it, and I had to do it on my terms,” Cox said.…