Point(1) = {0, 0, 0, 1};
Point(2) = {1, 0, 0, 1};
Point(3) = {1, 1, 0, 1};
Point(4) = {0, 1, 0, 1};
Point(5) = {2, 0, 0, 1};
Point(6) = {2, 1, 0, 1};
Line(1) = {2, 1};
Line(2) = {2, 3};
Line(3) = {3, 4};
Line(4) = {4, 1};
Line(5) = {2, 5};
Line(6) = {5, 6};
Line(7) = {6, 3};
Line Loop(1) = {3, 4, -1, 2};
Plane Surface(1) = {1};
Line Loop(2) = {-2,5,6,7};
Plane Surface(2) = {2};
Periodic Line {6} = {4};
Periodic Line {1} = {3};
Periodic Line {5} = {7};
Physical Surface("left") = {1};
Physical Surface("right") = {2};