E.C. Haines, 1964. An experimental variant of LISP1.5, implemented on the STRETCH computer. Basic structure was a trinary tree.
["The TREET Time-Sharing System", H.A. Bayard et al, Proc 2nd Symp Symb and Alg Manip, ACM (Mar 1971)].
[Sammet 1969, pp.457-461].
I will treet him cindely and giv him as gude edicatin as I hev got myself.