 The partition function is calculated from the maximal eigenvalue, resulting in a free energy per site of 
for
where formula_42 and formula_43 are the complete elliptic integrals of moduli formula_23 and formula_45.The eight vertex model was also solved in quasicrystals.There is a natural correspondence between the eight-vertex model, and the Ising model with 2-spin and 4-spin nearest neighbour interactions.