> Strongest was Cells[0], a library for Common Lisp CLOS. The earliest reference I can find is 2002[1], making it over 20 years old.

How about Microsoft DirectAnimation[1] from 1998, literally designed under the direction of Conal Elliott? Serious question, for what it’s worth, I’ve always wondered if all discussions of this thing are lost to time or if nobody cared for it to begin with.

[1] http://sistemas.afgcoahuila.gob.mx/software/Visual%20Basic%2...