Google is secretly building a social-gaming startup in an effort to create fledgling companies within the internet-search giant.

The founder and co-owner of the new firm, called Arcade, is Michael Sayman, according to people familiar with the matter. Sayman is the 21-year-old wonderkind who started as a Facebook intern at age 17 and left that company for Alphabet Inc.'s Google last year. Arcade's first app, slated to debut this summer, will have some elements of a trivia game. A Google spokesperson confirmed the existence of Arcade, saying it was "focused on mobile gaming with friends," without elaborating on specific products. "It's a very early experiment so there aren't many details to share right now." The effort is part of Area 120, a division where select employees can work on small startups that live inside Google. Arcade's games have no tie-in with existing social networks. Users create accounts with their phone numbers, one of the people said. Google is considering it a social-media investment because once a game gets to a certain size, it's something of a social network by itself, this person said.