Keystone on the Arch: Interlocking Curves

A close-up of a flat arch above a door. The joints between the stones forming the arch are not straight lines, but interlocking, zigzagging profiles, fitting together like a puzzle. Two contrasting colors make this interlocking shape clearly visible. The central keystone has the most complex design. Avoid: making the joints simple radial straight lines, arranging the two colors so that the interlocking shape is not visible, drawing fake joints with lines, making the arch a semicircle and losing the proportions of a flat arch.

Translated from Chinese by AI.

一道門上的扁拱近景。組成拱的石塊之間不是直線接縫,而是互相咬合的曲折輪廓,像拼圖一樣卡住,深淺兩色讓這個咬合的形狀被看得一清二楚。中央的鎖石造型最複雜。避免:把接縫做成單純的放射直線、讓兩色的排列看不出咬合的形狀、用線條畫出假的接縫、把拱做成半圓形失去扁拱的比例。