lc=10;

Point(1)  = {-4,0,0,lc};
Point(2)  = {0,-4,0,lc};
Point(5)  = {0,0,0,lc};

Circle(1) = {1,5,2};

//Extrude Line {1, {1,0,0}, {0,0,0}, Pi/2};
l1[] = Extrude Line {1, {1,0,0}, {0,0,0},  Pi/2};
Physical Surface(100) = {-l1[]};
//Physical Surface(100) = {13};