 In pursuit of the non-mereological composition strategy, Forrest (1986; 2006; 2016) relies on logically compound properties, in particular (in his 2016) conjunctive, existentially quantified and reflexive ones. Bennett (2013) argues that entities are part of further entities by occupying specific slots within the latter. Parthood slots are distinct from each other. Therefore, which entity occupies which slot matters to the composition of the resultant complex entity. Hawley (2010) defends the possibility of there being multiple composition relations. In a more general way, McDaniel (2009) points out that the relation of structure-making does not obey some of the principles of classical mereology. Mormann (2010) argues that distinct categories (to be understood as in  category theory)  come together with distinct parthood and composition relations.