The Austrian painter Thomas Ender was interested in exact reproduction of nature and unusual lighting conditions. In this oil sketch, he focussed on shell-like rock formations on Lake Leopoldstein in Styria. They stand out sharply against the turquoise-coloured water, in which the trees in the middle ground are reflected. The focus on the brilliance and the intense light of the foreground is emphasised by the mountain in the background. This is rendered almost as a monochrome surface, in paler shades of colour and with quick, rough brushstrokes.