Impermeable Barrier:
An impermeable barrier as it relates to human circulation is one in which the ability to move or see beyond the barrier is fully inhibited. Generally this would include an inability to see beyond the barrier's top or the bottom, but would not necessarily include seeing the horizontal ends of the barrier. The most common example of an impermeable barrier would be a full height partition or wall within a building that contains no impassable openings or screens and is not made with translucent or transparent materials, such as a partition constructed of gypsum board attached to wood studs.
This blog's early circulation diagrams are assumed to be using impearmeable barriers. Impermeable barriers have the tendancy to move the eye away from them, and thus, a person moving through a space will have a tendancy to move away from impermeable barriers. An example of this tendancy would be an individual who more or less walks down the center of a corridor. If there are no other individuals or objects to avoid, and the walls on either side are more or less the same, from my observation, the natural tendancy would be for an individual to center themself between the walls on either side. And according to this post, it would be because the individual would tend to move away from the two walls on either side with the same intensity.
This post is a sort of counterpoint to post 16, which discussed how individuals tend to move toward's open spaces.
