EntityQ191024· pop 34· linked from 40 articles15 puzzleSign in to savenumber game with 15 pieces but 16 spacesConnectionsSoviet UnionConceptMassachusettsEntityConnecticutEntityBostonEntityInternational Standard Book NumberEntityalgorithmEntityHartfordEntityBobby FischerEntityRubik's CubeEntitydigital object identifierEntityInternational Standard Serial NumberEntitySyracuseEntityhexagonEntityWorcesterEntitythree-dimensional spaceEntityparityEntitygraphEntitypermutationEntityJSTOREntitypuzzleEntityCategories19th-century fads and trendsCombination puzzlesMechanical puzzlesNP-complete problemsPermutations