OOPS can be seeded with a wide variety of programming languages.
For the experiments, we wrote an interpreter for a
stack-based universal programming language inspired
by FORTH [36].
We provide initial instructions for
defining and calling recursive functions, iterative loops, arithmetic
operations, and domain-specific behavior.
Optimal metasearching for better search algorithms is
enabled through bias-shifting instructions that can modify
the conditional probabilities of future search options in currently
running self-delimiting programs.
Sections A.1,
explains the basic data structures;
Sections A.2.1,
A.2.2,
A.2.3
define basic primitive instructions;
Section A.3 shows how to compose complex programs
from primitive ones, and explains how the user may insert them into total code 
.