 The arithmetical models used by Meyer and Mortensen later proved to allow inconsistent representation of the truth predicate. They also permit representation of structures beyond natural number arithmetic, such as rings and fields, including their order properties. Axiomatisations were also provided. Recently, the finite inconsistent arithmetical collapse models, a strictly larger class than those studied by Meyer and Mortensen, have been completely characterised by Graham Priest. Collapse models are obtained from classical models by collapsing the domain down to congruence classes generated by various congruence relations. When members of the same congruence class are identified, the theories produced are inconsistent. For example, Meyer’s initial construction collapsed the integers under the congruence modulo 2. This puts 0 and 2 in the same congruence class, so that in a suitable three-valued logic, both 0=2 and not-(0=2) hold. Priest showed that these models take a certain general form, see Priest (1997) and (2000). Strictly speaking, Priest went a little too far in including “clique models”. This was corrected by Paris and Pathmanathan (2006), and extended into the infinite by Paris and Sirokfskich (2008). Even more recently, Tedder (2015) obtained axiomatisations for the class of finite collapse models with a different background logic, Avron’s A3.