Of poplars and people, both blue. Stefan Pietryga is a painter and sculptor. The main figure in his sculptural work is the poplar, mainly in wood and with color, blue like the sky, but also cast in bronze, patinated green and black. His interest in this particular type of tree stems from an intensive study of Romanesque buildings. Pietryga works with saw and axe in rough and angular forms from the wood. To make them stand out in the landscape, he pigments them in ultramarine, the color that Yves Klein once established in contemporary art to evoke ideas of sky, depth, transcendence and immateriality.