lc = 1000.0; Point(1) = {-150000.000000,100000.000000,0.000000,lc}; Point(2) = {150000.000000,100000.000000,0.000000,lc}; Point(3) = {150000.000000,-100000.000000,0.000000,lc}; Point(4) = {-150000.000000,-100000.000000,0.000000,lc}; Line(1) = {1,2}; Line(2) = {2,3}; Line(3) = {3,4}; Line(4) = {4,1}; Physical Line(101) = {1}; Physical Line(102) = {2}; Physical Line(103) = {3}; Physical Line(104) = {4}; Line Loop(105) = {1,2,3,4}; Plane Surface(106) = {105}; Physical Surface(107) = {106}; Mesh.CharacteristicLengthMin = 200.000000 ; Mesh.CharacteristicLengthMax = 5000.000000 ; Mesh.CharacteristicLengthExtendFromBoundary = 0; Periodic Line {1,2} = {3,4};