This video shows how we can use our Robot Pebbles system
to duplicate complex 2D shapes.
We start by surrounding the original shape,
(the humanoid form shown in black), with Robot Pebble modules.
As the Robot Pebbles communicate, their connecting
bonds flash orange. The basic idea is to identify and
duplicate the modules on the border of the original shape.
The modules turn blue when they realize they may border
on the shape to be duplicated. Using a geometric algorithm,
the system differentiates between the blue modules that
border on the shape to be duplicated, and the blue modules
on the exterior on the composite block of material.
As each blue module determines that it borders on the
shape to be duplicated, it turns yellow, and sends a
message to its conjugate border module, that lies some
distance to the right. This offset distance is automatically
chosen by the system in such a way to ensure that the
original and duplicate shapes never overlap.
Once the conjugate border mirrors the border of the
original shape, the system performs a flood fill process
to inform all modules inside the new duplicate border that
they are part of the duplicate shape. As a result, they
turn orange. Finally, once all the modules that form the duplicate
shape have been notified of their unique status, the system
breaks all the unnecessary mechanical bonds, between
the other modules, leaving only the original and
the duplicate shapes behind.
We have extended this process to three dimensional shapes,
and we have run hundreds of experiments to demonstrate
that it runs reliably and robustly with any original shape.