  We describe a method for programming the autonomous navigation of active
colloidal particles in response to spatial gradients in a scalar stimulus.
Functional behaviors such as positive or negative chemotaxis are encoded in the
particle shape, which responds to the local stimulus and directs self-propelled
particle motions. We demonstrate this approach using a physical model of
stimuli-responsive clusters of self-phoretic spheres. We show how multiple
autonomous behaviors can be achieved by designing the particle geometry and its
stimulus response.
