lBox = 1. ;
Bl_Thick = 0.02 ;
cl_Far = 0.05 ;
cl_Bl = 0.001;

p = newp ;
Point( p   ) = { -lBox/2. ,  lBox/2.            , 0. , cl_Far } ;
Point( p+1 ) = { -lBox/2. , -lBox/2. + Bl_Thick , 0. , cl_Far } ;
Point( p+2 ) = { -lBox/2. , -lBox/2.            , 0. , cl_Far  } ;

l = newl ;
Line( l   ) = { p   , p+1 } ;
Line( l+1 ) = { p+1 , p+2 } ;

tmp[] = Extrude { lBox , 0. , 0. } { Line{ l   } ; } ;
s_Far = tmp[1] ;
tmp[] = Extrude { lBox , 0. , 0. } { Line{ l+1 } ; } ;
Hide { Line{ tmp[3] } ; }

Transfinite Line { -(l+1), -tmp[0] } = (Bl_Thick / cl_Bl) Using Progression 1.1 ;
Transfinite Line { tmp[2], tmp[3] } = lBox / cl_Far ;
Transfinite Surface { tmp[1] } ;
Recombine Surface { tmp[1] } ;

Physical Surface(1) = { s_Far , tmp[1] } ;

Mesh 2 ;
