Where the shape comes from
The step radical 彳 with its final stroke pulled long, the crossroads stretched into an open road that keeps going. A hand holding a rule to lay out a plan along it gives 建, to build, establish; a court reached by walking its length gives 廷, an imperial hall; and the road itself, simply continued, gives 延, to extend, prolong.
汉字 filed under 廴
No published character on HSK Guide is filed under this radical yet. 汉字库.