intriguing properties for it all to be just an accident." Simon P. Norton, an expert on the properties of the monster group, is quoted as saying, "I can explain what Monstrous Moonshine is in one sentence, it is the voice of God." McKay's E8 observation There are also connections between the monster and the extended Dynkin diagrams specifically between the nodes of the diagram and certain conjugacy classes in the monster, known as McKay's E8 observation. This is then extended to a relation between the extended diagrams and the groups 3.Fi24′, 2.B, and M, where these are (3/2/1-fold central extensions) of the Fischer group, baby monster group, and monster. These are the sporadic groups associated with centralizers of elements of type 1A, 2A, and 3A in the monster, and the order of the extension corresponds to the symmetries of the diagram. See ADE classification: trinities for further connections (of McKay correspondence type), including (for the monster) with the rather small simple group PSL(2,11) and with the 120 tritangent planes of a canonic sextic curve of genus 4 known as Bring's curve. Maximal subgroups The monster has at least 44 conjugacy classes of maximal subgroups. Non-abelian simple groups of some 60 isomorphism types are found as subgroups or as quotients of subgroups. The largest alternating group represented is A12. The monster contains 20 of the 26 sporadic groups as subquotients. This diagram, based on one in the book Symmetry and the Monster by Mark Ronan, shows how they fit together. The lines signify inclusion, as a subquotient, of the lower group by the upper one. The circled symbols denote groups not involved in larger sporadic groups. For the sake of clarity redundant inclusions are not shown. Forty-four of the classes of maximal subgroups of the monster are given by the following list, which is (as of 2016) believed to be complete except possibly for almost simple subgroups with non-abelian simple socles of the form L2(13), U3(4), or U3(8). However, tables of maximal subgroups have often been found to contain subtle errors, and in particular at least two of the subgroups on the list below were incorrectly omitted from some previous lists. 2.B centralizer of an involution; contains the normalizer (47:23) × 2 of a Sylow 47-subgroup 21+24.Co1 centralizer of an involution 3.Fi24 normalizer of a subgroup of order 3; contains the normalizer ((29:14) × 3).2 of a Sylow 29-subgroup 22.2E6(22):S3 normalizer