A second class of studies within the swell level, to which we will refer
again later, made significant uses of computer environments but as a tacit
medium in which the student's mathematical concept formation would be
studied (Edwards, 1991; Thompson, 1992; Thompson & Dreyfus, 1988).
These studies resemble the Logo studies of Clements and Battista (1989;
1990), Noss (1987), and Olive (1991), and the ISETL (Interactive Set Language)
study by Ayers et al. (1988). Here there was no emphasis
whatsoever on the computational medium itself or how it worked. The environments
were designed to promote the idea that students were to interact
with a model that behaved mathematically instead of giving the computer a
sequence of programming statements to be enacted.