A bstract We study M-theory compactified on twisted 7-tori with G 2 -holonomy. The effective 4d supergravity has 7 chiral multiplets, each a unit logarithmic Kähler potential. propose octonion, Fano plane based superpotentials, codifying the error correcting Hamming (4, 7) code. corresponding 7-moduli models have Minkowski vacua one flat direction. also superpotentials octonions/error codes for...