Ventive for Fireplace

include
aa=1.5;
ee=[[aa,0,-0.5],[aa,0,-0.2]];
ff=[for(i=[-0.2:0.1:0.5]) [-i*i*6 -8*i,0,i]];
gg=concat(ee,ff);

difference(){
tube([50,50,7], $fn=40, edge=gg);
tube([40,40,7], $fn=40);
}

module slat(length=44){
move([0,0,7/2], rVec=[90,0,60]) tube([7,3,length], $fn=80, basexy=false);
}


move([11,0,0]) slat(36);
move([0,0,0]) slat(40);
move([-11,0,0]) slat(36);

/*
move([0,0,-7]) difference(){
tube([44,44,7], $fn=40);
tube([40,40,7], $fn=40);
}

*/