  The notion of abstract Boehm tree has arisen as an operationally-oriented
distillation of works on game semantics, and has been investigated in two
papers. This paper revisits the notion, providing more syntactic support and
more examples (like call-by-value evaluation) illustrating the generality of
the underlying computing device. Precise correspondences between various
formulations of the evaluation mechanism of abstract Boehm trees are
established.
