For the purpose of our project, we defined a set of engagement mechanisms
designed to make the Geo more engaging to interact with.  These mechanisms can
be turned on and off with a flag, and can be summarized as follows:

Transition Animations: In the engagement version of the Geo, the Geo performs an
organic motion with sound effects when transitioning between states depending on
the confidence level and the change in the confidence level of the state that
it’s transitioning from.  These motions represent, variously, “Joy” at becoming
more confident, “Exasperation” at becoming less confident, “Boredom” at going
from low confidence to low confidence, and “Disappointment” at going from medium
confidence to medium confidence.  Going from high confidence to high confidence
triggers no motion.  In the non-engagement version of the Pleo, state
transitions are marked universally by a beep.

Reset Animations: In the engagement version of the Geo, the Geo does a
“stretching” motion with sound effects when being reset.  In the non-engagement
version of the Geo, the Geo simply makes a mechanical buzzing noise.

Blinking: The engagement version of the Geo blinks regularly (with some
randomness built-in to prevent uniformity).  The non-engagement version does not
blink.

Feedback Responses: In the engagement version of the Geo, the Geo will respond
to the user when touched either for the purpose of guidance or for the purpose
of reward/punishment.  Guidance feedback responses consist of the Geo bending
its head to look at the sensor area where the user is touching, while
reward/punishment produces organic sound effects corresponding to
positive/negative responses. In the non-engagement version of the Geo, no
feedback responses are given.