Before there was Twitter, there was Jenny Holzer. Her text-based art, equal parts sardonic observation and angry political commentary, punches you in the mouth with a wry smile. And now, at the ripe age of 67, she’s having a moment – or, better, she’s prolonging her moment. Holzer’s enigmatic work has been everywhere. In the late 1970s in New York City, she found her voice by anonymously posting cryptic aphorisms across Manhattan streets.