Many typefaces designed with a pen on paper (especially those from the 20th century) were licensed by different foundries, and were later independently digitized by them. Some special characters such as @ or the euro sign, were independently added later. Those “alternate cuts” are different digital versions of basically the same typeface design. They often vary in character set, letter proportions and kerning. Some are published under different names.
The idea for Duet started when I decided to create a complex, elegant, and easy-to-read script with particular emphasis using a double line feature in the capitals.