Imposing architecture: Tectus is based on a model and drawings under the names "System 618" by Jo Niemeyer from the year 1996. Tomohiro Nakamura picked and followed up with the idea to a later moment. The result is a timeless and creative toy for young and old. The many times by the golden ratio separated cube is covered by black areas. In the game those become fundamentals, walls or roofs and the player to real architects. Everything inserts very harmonic into each other. In mathematics and the arts, two quantities are in the golden ratio if the ratio of the sum of the quantities to the larger quantity is equal to (=) the ratio of the larger quantity to the smaller one. The golden ratio is an irrational mathematical constant, approximately 1.6180339887. Other names frequently used for the golden ratio are the golden section (Latin: sectio aurea) and golden mean. Other terms encountered include extreme and mean ratio, medial section, divine proportion, divine section (Latin: sectio divina), golden proportion, golden cut, golden number, and mean of Phidias. The golden ratio is often denoted by the Greek letter phi, usually lower case (φ). Mostly the line proportion is used in art and architecture as ideal proportion and as embodiment of aesthetic and harmony. For the Swiss company Naef it was a impulsion, to bring the object at the end of 2008 under the name "Tectus" on the market. Without Tomohiro Nakamura it would have never came so far, the idea and the copyright are Jo Niemeyers, who works with the golden ratio since centuries in the category of concrete art. For all Naef toys are only high quality woods from ecological plantation growth in Europe and only quality colours of highest amicability are used. From the baby age to the senior participants, the different products offer happiness and enjoyment and convey creativity and fantasy.