Alloy steel is steel that is alloyed with a variety of elements in total amounts between 1.0% and 50% by weight to improve its mechanical properties. Alloy steels are broken down into two groups: low alloy steels and high alloy steels. The difference between the two is somewhat arbitrary Strictly speaking, every steel is an alloy, but not all steels are called "alloy steels". The simplest steels are iron (Fe) alloyed with carbon (C) (about 0.1% to 1%, depending on the type). Corten Steel Sculpture was designed by Timothy Malone while he was a graduate student and part-time instructor at the University of Notre Dame. The Corten steel sculpture weighs 1,300 pounds (590 kg) and bears the Andrews University motto and the text "Corpus, Mens, Spiritus" on one side; the opposite side displays an imperfect circle that represents the globe and two curved meridian lines. It was supposed to be installed in December 1966, but was postponed until April 1967 due to Malone's illness and an "imbalance" in the sculpture.