# Self-supported three-dimensional structure made up of three or more sloping rods
Those beauty structures self-similar and with highly symmetric patterns don't need any glue or connections to stay stable.![tn1.JPG](https://steemitimages.com/DQmX1qSfxgFY7pGRt8sDjWZW8m9rdwZQVbh8JS9SX2p2Ecr/tn1.JPG)

## How to make one?
this structure is assembled by first installing a temporary central support that holds the first rafter at the correct height. The first rafter is fitted between the wall and the temporary central support and then further rafters are added, each resting on the last. The final rafter fits on top of the previous rafter and under the very first one. ] The failure of a single element may lead to the failure of the whole structure.![tn2.JPG](https://steemitimages.com/DQmV55nTX1L7JXPy7tfXfgvLWE4FEAWZKg2Czdd5GZHcthn/tn2.JPG)

## history
The reciprocal frame, also known as a Mandala roof, has been used since the twelfth century in Chinese and Japanese architecture although little or no trace of these ancient methods remain. More recently they were used by Architects Kazuhiro Ishii (the Spinning House) and Yasufumi Kijima, and engineer Yoishi Kan. 
![tn3.png](https://steemitimages.com/DQmRQNvniFFBajoUFn6gbovHKWQNBGr1gQ1RK3QuPamkCFo/tn3.png)
A clear example of using a reciprocal structure can be found in the Codex Madrid of Da Vinci where is described how to build bridge wood beams.
![tn4.jpg](https://steemitimages.com/DQmSLKtXrLcxueetD3bCh7fpPiUjjyrpWo79tDQGKv7K1Na/tn4.jpg)

![5n55.JPG](https://steemitimages.com/DQmaoK5SztpDESUaRC7ChXBtdS3BDLvwUVhMrpR5tRitJm2/5n55.JPG) 

![tn5.jpg](https://steemitimages.com/DQmVLmQHk5YQ3gUgMADynLUC3PHVBs1DFBBfpe34CXmvh9A/tn5.jpg)

![5n5.JPG](https://steemitimages.com/DQmUUeJbcp8kQuaY8E52xAgoUBm7xtnKqSdrrJKPiaQEKk1/5n5.JPG)