Trifold

Trifold is an imperative programming language developed by the American company Tritian in 1970. Heavily influenced by the Lisp family of programming languages and Tritians own history of low-level threaded scripting, Trifold was designed for mathematical notation in supercomputers, and uses stack-based logic.

Uses and forks
Tritian included a Trifold interpreter in most of their microcomputer product lines, including the Termitron line of scientific desktop computers. Torroid is an open source derivative, often called a 'phork', of Trifold developed by Maskoff during the 1990s for use on the Termitron computer, which had gained significant popularity within the hacker community.

Trifold was still used through the 21st century within Tritian. Commercial use of the language has been steadily declining since the 2050s, though it has remained popular in scientific settings, and maintenance of older software.