T i p s   &   T r i c k s   t o   o t h i c  G e o m e t r y   Tips & Tricks to Gothic: Trifoil | Ogee Arch | Equilateral Arch | Rose Window

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The double-curve ogee (oh-jee) was introduced from the Arab world in the 14th century and became popular throughout medieval England. It was also a favorite in Venice, Italy from where it derived its other moniker - the Venetian arch. It can also be referred to as a keel arch for its apparent resemblance to ship construction.

 

Campo Bandiera e Moro, Venice.		World Trade Center, New York.
Here, the construction begins with an equilateral triangle, the simple rule of thumb for which is - all sides are equal. Now adjust your compass to half the length of the baseline, and from point A construct a semicircular arch.		With your compass still adjusted to half the length of the baseline, construct a concave arch from point B. Repeat at point C.