Complex sentence: In 1992, the series was reissued with two changed elements in order to fight counterfeiting: the elliptical perforation and variable-coloured ink (golden to green depending on the angle of view) used to print the Queen's profile.
Split into simpler sentences: In 1992, the series was reissued with two changed elements, in order to fight counterfeiting. An elliptical perforation was added to the sides, and Optically Variable Ink (OVI), which appears green or gold depending on how it is viewed, was used to print the Queen's profile.