Reflection of a watermill on the surface of the water in the eveningReflection of a watermill on the surface of the water in the evening
Where is the water surface, and where is the sky, everything has mergedWhere is the water surface, and where is the sky, everything has merged
The heavenly surface of the lake on the background of the mountainThe heavenly surface of the lake on the background of the mountain
В математике: граница, отделяющая геометрическое тело от внешнего пространства. Наружная сторона чего-н..