Signing exact English (SEE2) was developed by Gerilee Gustason, Esther Zawolkow, and Donna Pfetzing in the early 1970s. As an offshoot of SEE1, many features of SEE2 are identical to that code system. Initializations and grammatical markers are also used in SEE2, but compound words with an equivalent ASL sign are used as the ASL sign, as with butterfly. SEE2 is also used in Singapore. About 75% to 80% of SEE2 signs are either borrowed from ASL or are modified ASL signs.