! oct_frame  /rewritten 2/22/94/***VL/
! a, b, frame width, frame thickness,
! glass material, internal frame width
!print a,b,c,d,e,f

k=f                        ! internal frame width
v=sqr(2)-1
z=a/2
w=b/2
g=1-2*c/a
h=a/2-c
i=b/2-c
if g<0.0001 then 20
if h<0.0001 then 20
if i<0.0001 then 20
j=1-k/h
l=z*g/h
m=w*g/i

addy b/2
mulx z
muly w

prism_ 18,d,
1,v,15,
v,1,15,
-v,1,15,
-1,v,15,
-1,-v,15,
-v,-1,15,
v,-1,15,
1,-v,15,
1,v,-1,
g,v*g,15,
v*g,g,15,
-v*g,g,15,
-g,v*g,15,
-g,-v*g,15,
-v*g,-g,15,
v*g,-g,15,
g,-v*g,15,
g,v*g,-1

del 2
addz d/4
mulx h
muly i

prism_ 18,d/2,
l,-v*m,15,
v*l,-m,15,
-v*l,-m,15,
-l,-v*m,15,
-l,v*m,15,
-v*l,m,15,
v*l,m,15,
l,v*m,15,
l,-v*m,-1,
j,v*j,15,
v*j,j,15,
-v*j,j,15,
-j,v*j,15,
-j,-v*j,15,
-v*j,-j,15,
v*j,-j,15,
j,-v*j,15,
j,v*j,-1
body 1
if e=0 then 20
!*** glass only
addz d/4-0.002
material e
prism_ 9,0.004,
j,0,15,
j,-v*j,15,
v*j,-j,15,
-v*j,-j,15,
-j,-v*j,15,
-j,v*j,15,
-v*j,j,15,
v*j,j,15,
j,v*j,15
body 1
20:
end
