Concentric stranding—--A wire or core in the middle of a conductor surrounded by one or more spiral layers of strands.
Bunch stranded—--The units in the conductor are not arranged in geometric shape, but only in the same direction.
Stranded—--The core of the conductor is a concentric strand or bundle of strands around which one or more strands of concentric strands are stranded in concentric fashion.

Cupric direction
Left stranded:That is, the stranded wire is counterclockwise direction, also known as "Z strand". When viewed from the surface of the conductor, it takes the form of (\\\\\\\\\\\\\\\\\\\\\\\)
Right Winch:That is, the stranded wire is clockwise direction, also known as "S strand", from the surface of the conductor when viewed in the form of (////////////).