The 5x5 chair is a typical design project where the limitation is recognized as a challenge. The chair's seat and the back are made of xilith which is very difficult to be shaped. Xilith is the raw material that can be found 300 meters under the ground surface and is comined with a coal. But it is nither the coal nor the wood. Currently the majority of the raw material is thrown away. From environmental point of view this material generates waste on the earth surface. Therefore the idea about chair design seemed to be very provocative and challenging. The scientific methods of the material's final surface treatment have been explored so if applied properly the final look can be close to that of ebony. Each chair is unique as neither two tiles look the same. Therefore the chair can have more brown or more black look depending on the tiles collected together.