Pixel art
Below, you can see two fragments of the World's Tallest Vistual Building. This building was constructed from parts, which were contributed by many artists over the world. Each part is a single floor of the building, which equal dimesions of floor and ceiling. So, every part can be put together with other parts. Concatenated to each other parts forms the very tall skyscraper. It's one of the most remarkable artwork in pixel art.
You can see two variations of impossible staircases in the building. The first one (with cows on the staircase) was created by Cow23, the second by Brian Suda.