Applied to human behaviour, the need to bound means a need to add another layer around the individual. It is as if one was an onion with the skin layer missing. Once satisfied, there are two possible directions for bound. As we will see, the former is a vertical movement whereas the latter is a lateral movement. The second level of impurity is bond.
Bond is a derivative of blend.
Transformation is not quite achieved and we have only achieved a tight relationship, although somewhat closer than that of bound. In human behaviour, using the bias to yin, and receptivity, as an example, we are dealing with an identification, or relationship, with something, or someone, rather than the reception, or assimilation, of something, or someone. The need to bond means a need to fill a hole within part of oneself. This is not as strong as the blend bias of filling all of oneself. The final level of impurity is that of bind.