This paper describes how genetic programming has been used as an invention machine to automatically synthesize complete designs for four optical lens systems that duplicated the functionality of previously patented lens systems. The automatic synthesis of the complete design is done ab initio, that is, without starting from a preexisting good design and without prespecifying the number of lenses, the topological arrangement of the lenses, or the numerical or nonnumerical parameters associated with any lens. One of the genetically evolved lens systems infringed a previously issued patent, whereas the others were noninfringing novel designs that duplicated (or improved upon) the performance specifications contained in the patents. One of the patents was issued in the 21st century. The designs were created in a substantially similar and routine way, suggesting that the approach described in the paper can be readily applied to other similar problems in the field of optical design. The genetically evolved designs are instances of human-competitive results produced by genetic programming in the field of optical design.