MARBLE — Their faces ghostly white, the sculptors carefully conjure their visions from blocks of stone. With screaming machines, the art appears. An ocean wave. A distorted face. A great ape. A leafy forest. A constellation. “What does it look like to you?” says Heidi Treleven, stepping back from her creation. She grabs a cup of water and pours it over the top of her three-sided sculpture — and the Yule marble glistens like a rolling sea of diamonds. Treleven and her husband were up in Marble a week ago.