Probability can also be included in the production
rule that constructs recursion in JavaMAL microworld. For
example, Figure 8 is the context where a turtle slides down
on skis from the top of the hill to the bottom. When making
recursion by using dummy variable B, probability of 50% of
‘RB’, coming down to the right, and probability of 50% of
‘LB’, coming down to the left, are ordered by B=‘RB, LB’
symbol. Recursion occurs three times by ‘do_3 B’ symbol,
and the turtle ends up with different positions via different
routes every time. Such a recursion experimental
environment including probability can be extended to
combinational thinking or mathematical exploration on
normal distribution.