The Reuleaux Triangle was designed by the German engineer Reuleaux in the 19th century.
After that, the mathematics community extensively studied its utility. By the twentieth century, it was cited in mechanical engineering,
The most famous example is the application in pistonless engines, Volkswagen Beetle, Master Mazda RX7,
Both use this new design of the engine (Rotary Engine / Wankel Engine).

postscript:
Unexpectedly to study the Lego Rotary Engine built by Japanese engineer Akiyuki,
It will be related to Ryosuke Takahashi's Mazda RX7 from "Initial D".
This sports car is really cool, in addition to the appearance of the body,
The main reason is that its exhaust pipe will spit fire during competitions.
Unfortunately, the film of "Initial D" did not emphasize this point with the lens...
The rotary engine is the key to the fire-breathing exhaust pipe of Mazda RX7!

魯洛三角形 (Reuleaux Triangle)是十九世紀德國工程師Reuleaux的設計，
之後數學界廣泛研究它的效用。到二十世紀，被引用於機械工程，
最著名的就是應用3在無活塞引擎，福士甲蟲車、萬士達Mazda RX7，
均使用了這款轉子引擎 (Rotary Engine / Wankel Engine)。

後記：
想不到研究日本工程師Akiyuki砌出的轉子引擎(Lego Rotary Engine)，
會跟《頭文字D》高橋涼介的Mazda RX7扯上關係。
這輛跑車所以這麼酷，除了車身外型之外，
最主要是因為它的排氣管在賽事中是會噴火的，
可惜《頭文字D》的影片並沒有用鏡頭強調這點......
而轉子引擎就是Mazda RX7排氣管會噴火的關鍵！

In Greek mythology Sisyphus was the king of Ephyra (now known as Corinth). He was punished for his self-aggrandizing craftiness and deceitfulness by being forced to roll an immense boulder up a hill only for it to roll down when it nears the top, repeating this action for eternity. Through the classical influence on modern culture, tasks that are both laborious and futile are therefore described as Sisyphean. (Info from Wikipedia)

在希腦神話裡，西西弗斯是Ephyra國王，因為他的罪行，被罰到在山上將巨石推上山頂，當巨石推到山頂，巨石又會滾落山腳，於是西西弗斯就要沉淪於不停重覆的推巨石上山的苦工之中，世人借西西弗斯的懲罰，比喻人們生活於無止境的苦役之中......

Strandbeest is originally designed by Dutch artist and engineer, Theo Jansen. This Lego set is a Lego MOC set. It is operated by 2 Lego M motors and can be played with Lego remote controller. The action of the legs is similar to the galloping of the horse.

仿生獸源於荷蘭工程師兼藝術家Theo Jansen的設計。這套LEGO並非官方的設計，由兩個中型LEGO摩打，附以IR紅外線接收器控制。而這套仿生獸腳部的行走動作，乃模仿馬匹的行走形態。

For the preparation of the Open Day in E.C.F. Saint Too Canaan College, I prepare a Lego Drawing Machine to draw the pictures as a special gift for the visitors. This machine can draw over 20 different pictures if you change the position of the liftarms' pivot point.

為了預備基督教中國佈道會聖道迦南書院的開放日，我特別預備了Lego機械繪圖機，為來賓繪製幾何圖案，成為訪客的特別禮物。隨著改變機械臂交接點的位置，這部繪圖機能夠繪製出超過20多款式的幾何圖案。