Ernst Niederleithinger stands at the edge of an industrial laboratory in the south-western suburbs of Berlin.

It is nearing sunset, a week before the summer solstice. The room is illuminated from above by angled skylights reminiscent of a 19th-century painter’s studio. Around him in the gloom stand more than two dozen concrete monoliths, many half a metre thick, some close to two metres tall. A few weigh as much as 700kg. Drawn across their smooth, grey surfaces in pencil and ink are precisely measured grids, often grids within grids, at different scales. These inscriptions give the objects an archaeological feel, like exotic obelisks waiting to be interpreted.

Gazing at the monoliths, Niederleithinger knows he can do the impossible: he can peer inside solid concrete, examining the depths of even the densest material. Although the massive shapes lurking inside are nothing more than oversized blocks, Niederleithinger cautions against any notion of simplicity. “Concrete,” he says, “is very complicated.”