John Carmack cut his ties with Meta Platforms, a holding company created last year by Facebook founder Mark Zuckerberg, in a Friday letter that vented his frustration as he steeped down as an executive consultant in virtual reality."There is no way to sugar coat this; I think our organization is operating at half the effectiveness that would make me happy," Carmack wrote in the letter, which he shared on Facebook.Carmack's departure comes at a time that Zuckerberg, Meta's CEO, has been battling widespread perceptions that he has been wasting billions of dollars trying to establish the Menlo Park, California, company in the "metaverse"—an artificial world filled with avatars of real people.Although Carmack had only been working part time at Meta, the dismay that he expressed seems likely to amplify the questions looming over Zuckerberg's efforts to become as dominant in virtual reality as Facebook has been in social networking since he started the service nearly 20 years ago while attending Harvard University.Zuckerberg began to explore virtual reality in earnest in 2014 with Facebook's $2 billion purchase of headset maker Oculus."