Kevin Müller cut the shadow of a tree into two sheets of tarpaulin at the Muthesius Academy of Fine Arts in Kiel, Germany. It began as his bachelor’s project, and in 2025 it hung over the city’s Old Market. The sail, called Sense Of Shade, throws moving patches of light on the ground like a tree canopy.
The project’s own readings put the pavement beneath the sail at 77.9°F to 79°F (25.5°C to 26.1°C). Shade from a maple read 79°F (26.1°C), and stone in full sun hit 99.5°F (37.5°C). The project does not say anyone outside the team has checked those numbers.
Leaf patterns from canopy photographs
The idea came during the final, stressful stretch of his degree, Müller told a regional chamber of commerce. “I was stressed, withdrew into nature and watched how light and leaves work together,” he said. The chamber, IHK Schleswig-Holstein, printed that remark in German.
With two fellow students, he photographed tree crowns and had the leaf shapes pulled out digitally. He then cut patterns into different materials. Stacking layers strengthened the play of light and shadow, the chamber reports, and the final design mixes horizontal and vertical leaves.
Today the project’s concept page describes “two taut, tear-resistant tarpaulin panels with a cut-out tree pattern.” According to that page, the panels also produce leaf-like rustling sounds.
Laser readings on sealed stone
Müller’s team took its measurements during an exhibition, on 1,076 square feet (100 square meters) of sealed stone. The thermometer pointed at the ground from about 3.3 feet (1 meter) up. It recorded the temperature of the surface, not the air.
Photos on the concept page show 77.9°F and 79°F beneath the sail. Under a maple, a spot of sunlight between the leaves read 90.5°F (32.5°C). Shaded stone there read 79°F.
A beach umbrella gave the team 78.6°F (25.9°C) in full shade. That result sits very close to both the fabric and the tree. Bare stone in direct sun ran about 20 degrees hotter than the shade from the sail.
On this limited evidence, the sail keeps sun off stone about as well as an umbrella. The company sees its advantage elsewhere, in the gaps and the look of the light. Its page promises “good air circulation” that “prevents the greenhouse effect under sail.”
Kiel paid for the installation
City money helped carry the sail out of the art school, according to the chamber’s magazine. Kiel funded the Old Market installation from its budget for art in public space. The city also praised the artistic intent.
Müller still calls it a product, aimed at private customers, companies, towns and cities. In 2024 he registered the pattern as a German utility model. That is a lighter form of patent protection.
Besides the Old Market, the project lists shows at the Alte Mu in 2024 and the Waterkant Festival in 2025. A Muthesius exhibition called Insight Outlook also displayed it in 2025. All of them took place in Kiel.
Neighbors who built a company
Müller’s business partner, Titus Bötel, started out as his neighbor. A company blog post from July 6, 2026 says the two chose not to let the idea end as a student project.
Bötel holds a business master’s degree from Kiel University and handles strategy, financing and sales. Müller runs design and technical development. A Schleswig-Holstein startup grant now supports work on a market-ready version, and the shop page still reads “coming soon.”
“We do not want to view shadows as a byproduct,” the post says. The company gives its fabric a lifespan of up to 12 years. It also says it is researching bio-based alternatives.
Real trees still do more
Müller himself stresses that his product cannot replace a tree, the chamber’s article notes. Trees cool the air by releasing water through their leaves. A sheet of tarpaulin cannot do that.
A 2023 study in The Lancet looked at 93 European cities in the summer of 2015. It linked urban heat islands to about 6,700 premature deaths. Raising tree cover to 30 percent would cool those cities by an average of 0.7°F (0.4°C) and could prevent about 2,644 deaths, the authors estimated.
Cities keep investing in canopy for that reason, as Singapore’s million-tree program and research on Chicago’s mature trees show. Trees need soil, water and decades, though. Some paved places therefore try other fixes, like cooler porous pavement.
Rain and air readings stay unpublished
The published numbers cover one kind of surface during one exhibition, taken by the team that sells the sail. The project has not released air temperatures, wind tests or a comparison across a full season.
Rain remains another open question for anyone planning an installation. The official pages call the sail weather-resistant but do not explain how it handles a downpour.
The 12-year lifespan is the company’s own figure as well. And Müller’s statement to the chamber that such shadow patterns are demonstrably restful came without a study attached. His site lists no price either, so towns cannot yet compare the sail with awnings or planting.
Photo: Sense Of Shade
