This Kaleider screen image shows the outline of a Skewed Cone 3D Mirror that was created with the Fit to Image option so that it encloses the entire picture.  The mirroring surface is defined by a yellow rectangle, which can be resized by clicking and dragging any of the yellow adjust boxes.  The red lines represent the relative height of the cone, adjustable by the red box.  The green line indicates the degree of 'skew' of the cone, which can be varied via the green box.  The relative distance of the source image above the surface is denoted by a blue line, and can be altered with the associated blue box.  Just press Render (or the Space bar) to render an effect.  (In this example, the Tile Source Image option has been set in the View Menu, so since the source image is smaller than the screen size, it is mirrored across its edges to fill the screen.)