United States Patent: 5,533,051
Apparently you really can patent nonsense. In United States Patent 5,533,051, we get the following intriguing claim:
A second aspect of the present invention which further enhances its ability to achieve high compression percentages, is its ability to be applied to data recursively. Specifically, the methods of the present invention are able to make multiple passes over a file, each time further compressing the file. Thus, a series of recursions are repeated until the desired compression level is achieved.
Any first year computer science student taking any kind of discrete math should be able to tell you what is wrong with this claim.