The opening cross-section of the blast nozzle arrangement is essentially symmetrical to the longitudinal axis of the yarn channel.

Core pole shoes 6, in the shape of a ring, from the side of horseshoes and the axis Z are equipped with rounded projections IfJ positioned symmetrically to the axis d of a pole shoe.

This groove can be symmetric or asymmetric in relation to the longitudinal axis of the plug and its walls can have rectangle shape or the other shape made in correspondence with some function.

A hollow cylindrical control tube (24) is secured to rear seal (22) so that control tube (24) is symmetric with axis (18).

The lens (6) is symmetric about the axis of rotation (8) of the array.

Each coil arrangement has a plurality of coils (3, 4, 11).

The shell consists of two convex, interspaced shell elements that are symmetrically opposite in relation to the x axis and the y axis, and are interconnected by connection elements at least in the region of the carrier lugs.

An inner coil (3) which is axially symmetrical in relation to the normal axis (2) is surrounded by an outer coil (4) which is axially symmetrical in relation to the normal axis (2).

The vibration absorbing device is connected to the shaft in an axially symmetric way.

The arrangement of articulated connectors about the transverse centerline is symmetrical.

The support surface is also symmetrical about the longitudinal axis.

The acoustical sensor has a reception function that is symmetrical about the axis and the axis is substantially perpendicular to the base surface.

The axis of the piezoelectric actuator (7) is symmetric to two slide table rail pairs.

The shape of the flywheel is formed by the rotation symmetrical with respect to the axis of rotation and an axis perpendicular to the axis of rotation of a geometrical figure which rotates thereabout.

The resultant photo-disrupted tissue creates a layer which is substantially centro-symmetrical around the optical axis.