Next-to Condition

Definition:	The Next-to condition checks to see how many of the 8 adjacent neighbors in the same layer have a certain shape. If the agent is next to the right number of the specified shapes, the condition is true. Otherwise, the condition is false.
Parameters:	comparator, formula, shape
Example:	The Particle agent in the Accretion 3D project checks if it is next to at least one stationery Particle in the same layer or in the layers above (+1) or below (-1). If so, it changes itself to be a stationery Particle, increments a count and maps its color to a shade, based on the current count of stationery particles.