There are several objects which can be used in the `PSlab`. They are all subclasses of either
`_GeometryObject2D` or `_GeometryObject3D` which consequently are derived from
`_GeometryObject`. All the geometry objects don't have any useful methods other than
constructors in which all the necessary informations concerning position, size and material
should be given.

There are some common parameters which can be provided to the constructor of any object:

`epsilon`- is the value of dielectric constant of the object. It can be either
a single isotropic value or a sequence of three diagonal elements of anisotropic
diagonal tensor (non-diagonal anisotropy is not supported by the
`PSlab`). `mu`- the magnetic constant of the object. It is set in simmilar way as
`epsilon`, but can be omitted in which case its default value is . `smooth`- the smoothing parameter of the object. The default value is the
`smooth`parameter of the geometry. See the desctiption of`smooth`member in section 4.1.1 for more details.

In two-dimensional geometry (`Geometry2D`) there is only one possible object to be defined:

**class**(`Rectangle``self, left, right, epsilon`[`, mu`[`, smooth`]`]``)`-
Rectangle in plane in
`Geometry2D`. The`left`and`right`are the positions of the sides of the rectangle.

3D geometriy (`Geometry3D`) can contain the following objects:

**class**(`Cylinder``center, radius, epsilon`[`, mu`[`, smooth`]`]``)`-
Cylinder with axis perpendicular to the layers. The
`center`must be a sequence of two numbers containg and coordinate of the cyulinder center. The meaning of`radius`is obvious ;).

**class**(`Cuboid``corner1, corner2, epsilon`[`, mu`[`, smooth`]`]``)`-
A cuboid with it's sides paraller to and axis.
`corner1`and`corner2`should both be sequences of two numbers containg and coordinates of the oposite corners. If and , then all the corners of the cuboid in plane are , , , and .