default width = 4
default height = 3
default radius = 0.5
default b_width = 2;
default b_height = 0.5

let w2 = {width/2 - radius}
let w = {width - 2*radius}
let h = {height - 2*radius}
let dw = {(w - b_width)/2}

H w2;
q radius,0 radius,radius
v h ;
q 0,radius -radius,radius
h -dw ;
v -b_height ;
h -b_width ;
v b_height ;
h -dw;
q -radius,0 -radius,-radius
v -h;
q 0,-radius radius,-radius
X