阶梯中线与两侧斜栏

依据抵达点当前真实近景，只取阶梯中线、两侧斜栏及其连接细节，不把画外结构当作事实。

作品只描绘阶梯中线、两侧斜栏和连接细节。The work shows only the stair centerline, sloped side rails, and their joints.