In Toontalk ‘rule’ is represented as an entity that expresses potentials for action. The
realisation of rules in Toontalk marks the relation between mathematical and
everyday concepts, while other applications such as Logo Imagine represent ‘rule’ as
a mathematical explanation that underlies everyday experiences. Toontalk provides
the user with the potential to move between everyday and mathematical concepts on
screen, without privileging either. Toontalk represents ‘rule’ as a way to connect
(make sense of) the everyday and the mathematical.
An everyday notion of ‘object’ is present in Toontalk, where an object has to be
visually depicted - it has to ‘be’ something. In Toontalk the link between ‘rule’ and
object is maintained through the object’s sensors which provide inputs to the robot.
This link is two-way, for example, if the object is picked up and moved, the
horizontal position sensor will change, conversely if the value of the latter is altered,
the object will move. A rule can be transferred from one object to another by placing
it on the back of an object. The sensors in the input will now refer to the new object.
An object is thus named in two ways first by its presence on the screen as an entity
and secondly in mathematical terms as a set of descriptions through its sensors, (e.g.
position, size, shape etc.).
The entity ‘rule’ is shaped by the multimodal configuration of the Toontalk program
mode. The seemingly fixed unidirectionality of the written text (from left to right, and
top to bottom in the west) present in other computer programming applications (for
example, Imagine Logo and Pathways) is not apparent in Toontalk. In Toontalk the
arrangement of the different elements of programming mode have multiple
directionality, which disturbs the logic of the traditional 'line' of western writing as a
‘textual/written unit’ in which readers move (their gaze) from element to element
from left to right. Within Imagine and Pathways, ‘condition’ and ‘action’ are
represented as distinct entities through the sequential order of the ‘rule’. In Imagine
Logo this is a consequence of the modal representation and of the move from left to
right in western writing. In both instances the condition is foregrounded by this
175