Plain ol’ white paper. It may not sound exciting, but Callesen’s artwork is conceptual, intricate, detailed, thrilling and made of nothing-super-special white paper. Finely cut mostly from a single sheet, 3-D shapes rise up as delicate sculptures, juxtaposed from the cut-away negative space. The craft requires much planning and is unmistakably well-executed. Yet there’s an elementary-school innocence about it, perhaps because his work often shares fairytale themes, like those of fellow Dane Hans Christian Andersen. Callesen’s sculptures range from minuscule to life-size, as in the Escheresque installation “Parallel Stairs.” His work is about reflecting on the divine, life and death, but his floating castles—vast enough to accommodate human inhabitants—are a grown-up kid’s fantasy come true.