Letters, cheques, petitions, lottery tickets, contracts, and passports. Writings are partially visible imprints that occur on a sheet of paper beneath the apparent writing. They may be caused by ink blots, watermarks, or other marks present in the paper. The word "ink blot" is also used to describe any such mark. Ink blot patterns are commonly seen in letters and documents written with a pen or pencil. In addition to being interesting artifacts in themselves, writings that contain ink blotches can provide evidence for dating events (such as when a letter was written) or contents (such as secret messages). Because of this last point, criminals have been known to write misleading words in letters they send out so that if their handwriting is found in a book it will appear to date from after the theft was committed. Criminals have also used ink blotting to hide their identity. If an unknown person writes a letter with clear ink blobs then it cannot be said with certainty whether that person is male or female, old or young. As more modern pens become available with different colors of ink it becomes harder still to identify the writer. In conclusion, writings containing ink blotches can provide evidence for dating events or contents not readily apparent from just looking at the writing itself.