Pixie Scheme was written in C, specifically in Macintosh Programmer's Workshop (MPW) C version 2.0.2. I developed Pixie Scheme on a plain vanilla Macintosh II with 1 MByte of memory. I later bought some more memory, and ported Pixie Scheme to later versions of MPW C ΓÇö currently, 3.2b3.
Many failings or biases in the first release of the program no doubt reflected the specific nature of my environment. (For example, 1 MByte wasn't enough memory to test Pixie Scheme adequately under MultiFinder.)