Mathematica notebooks related to imaging with two skew ideal lenses

Mathematica notebooks containing detailed calculations of image positions for a general system of two skew ideal lenses. <br> TwoParallelLensProof.nb: Mathematica document in which the image position is calculated due to a system of two parallel non-coaxial lenses, both in cartesian and lens-imaging coordinates. <br> TwoLensProof2D.nb: Mathematica document in which the image position in two dimensions is calculated due to a system of two skew lenses, both in cartesian and lens-imaging coordinates. <br> TwoLensProof.nb: Mathematica document in which the image position in three dimensions is calculated due to a system of two skew lenses, both in cartesian and lens-imaging coordinates. <br> Mathematica documents can be viewed either in Mathematica, which requires a license, or in the Wolfram CDF player, which is freely available from the Wolfram website, currently at https://www.wolfram.com/cdf-player/ .