. 2011 Dec 8;5:57. doi: 10.3389/fncom.2011.00057

Table 1.

Primitives of the G-code, representing atomic cellular behaviors, with their input/output ports and parameters.

Primitive	Input ports	Output ports	Parameters
`move`	speed	speed
	direction^v	direction^v
`secrete`	rate		substance_name
			substance_type
`detect`		gradient^v	substance_name
		concentration	substance_type
`attach`	receptor_expression	adhesion_force	(static\|follow)
`morph`	diameter	diameter
	tension	tension
	color	color
		cell_density
`fork`	probability_to_fork	has_forked^b	daughter_diameter
	direction^v		machine_name
`synapse`	spine_formation	connection_density	(excitatory\|inhibitory)
	bouton_formation
	connection_probability
`replicate`	probability_to_replicate	has_replicated^b
	direction^v
`die`	probability_to_die	has_died^b
`instantiate`	probability_to_instantiate	has_instantiated^b	machine_to_instantiate
`kill`	probability_to_kill	has_killed^b	machine_to_kill

v denotes ports with a vectorial value, all other ports have a scalar value; b denotes scalar ports with a boolean value; the parameter “substance_type” in secrete and detect takes one of the following values: “extracellular,” “intracellular,” or “membrane_bound.”