Cassowary is an incremental constraint-solving toolkit that efficiently solves systems of linear equalities and inequalities.
Cassowary was developed by Greg J. Badros, Alan Borning, and Peter J. Stuckey, and was optimized for user interface applications.
These allow designers to describe the layout of a web page in a more flexible manner.
The original distribution,[2] unmaintained since 2000, included Smalltalk, C++ and Java implementations, along with bindings for GNU Guile, Python, and STk.
Third-party implementations exist for JavaScript,[3] Dart,[4] Squeak,[5] Python,[6][7] the .NET Framework,[8] and Rust.