! Document name: half_grid_4

!1/2_grid_4  11.07.1989.
!internal macro: -

pars a,b,frame width

let d=1"

let z=a/2-c
let f=b-c

let n=a/4+d/2
let o=a/4-d/2
let p=b/2+d/2
let q=b/2-d/2

let m=1.414

poly_ 26,
o,c,1,
n,c,1,
0.966*n,0.259*p,1,
0.866*n,0.5*p,1,
0.707*n,0.707*p,1,
0.5*n,0.866*p,1,
0.259*n,0.966*p,1,
0,p,1,
-0.259*n,0.966*p,1,
-0.5*n,0.866*p,1,
-0.707*n,0.707*p,1,
-0.866*n,0.5*p,1,
-0.966*n,0.259*p,1,
-n,c,1,
-o,c,1,
-0.966*o,0.259*q,1,
-0.866*o,0.5*q,1,
-0.707*o,0.707*q,1,
-0.5*o,0.866*q,1,
-0.259*o,0.966*q,1,
0,q,1,
0.259*o,0.966*q,1,
0.5*o,0.866*q,1,
0.707*o,0.707*q,1,
0.866*o,0.5*q,1,
0.966*o,0.259*q,1

poly_ 5,
0,c,1,
d/m,c,1,
0.707*z+d/m/2,0.707*f-d/m/2,0,
0.707*z-d/m/2,0.707*f+d/m/2,1,
0,d/m+c,1

poly_ 5,
0,c,1,
-d/m,c,1,
-0.707*z-d/m/2,0.707*f-d/m/2,0,
-0.707*z+d/m/2,0.707*f+d/m/2,1,
0,d/m+c,1

poly_ 5,
0,d/m+c,0,
d/2,d/m+c+d/2,1,
d/2,b-c,0,
-d/2,b-c,1,
-d/2,d/m+c+d/2,0

del top
end