Among the most interesting things about John McLaughlin’s paintings are their imperfections. A self-taught California minimalist born in 1898, McLaughlin started painting full-time only in 1946, after he’d served in both world wars. From a distance, his straight-edged geometric compositions look aloof and precise, but up close, they’re idiosyncratic, at least a little worn and a lot warmer than you’d expect. The artist bought his painting supplies at Sears, which is among the reasons many of his works didn’t age too well. The white behind two sets of identical yellow, blue and black bars has yellowed slightly. As part of as part of McLaughlin’s overdue exhibition at LACMA, the curators installed chairs — made specially by artist Roy McMakin — so you can stay and spend time with the work, as if they’re old friends with whom you need to catch up.