外展隙
The embrasures are between 14 and 30 inches in height and are usually recessed. 枪炮眼通常高14到30英寸，而且通常凹进掩体壁。
Jiaqing cannon with Ruyi knot,not renovated yet,with inscriptions up and down.It has embrasures up and down,wonder which side is up. 有如意结的嘉庆炮，没清理，上下都有铭文，而且上下都有点火的炮眼，都不知道那面在上，那面在下。
Deep embrasures as well as the sculptural effect of the building mass create a vivid picture of light and shadows but without distraction from the overall form. 建筑体凹凸有致,具有雕塑性造型,经由外立面的光影效果,形成生动活泼的画面,并不与整体效果冲突。
When the facial embrasures are opened, it is possible to increase the area of light deflection (shadows) and to reduce virtually the tooth smooth surface width (area of light reflection). 唇侧外展隙打开的时候，此处光线偏转区面积（阴影区）增加，使视觉上牙齿唇平面宽度（反光区）减小。
protected with battlements or parapets with indentations or embrasures for shooting through. 用锯齿状的和有可以射击的枪眼的城垛、胸墙保护。
