[x55,x89]
;lang4s, modified for 4-fold symmetry
; x55 - angular distance
; x99 - ration of projection that moved further than x55
;ACO(<Expression>)   arc cosine of expression (in degrees)
fr
?previous angular document file?
fr
?current angular document file?

ud n,x51
<1>
;
x89=0
do lb1 i=1,x51
ud ic,x0,x21,x22,x23
<1>
do lb5 i=1,3
if(x23.lt.90.0) goto lb6
x23=x23-90.0
lb5
lb6

x81=COS(x23)*SIN(x22)
x82=SIN(x23)*SIN(x22)
x83=COS(x22)

ud ic,x0,x41,x42,x43
<2>
do lb7 i=1,3
if(x43.lt.90.0) goto lb8
x43=x43-90.0
lb7
lb8

x84=COS(x43)*SIN(x42)
x85=SIN(x43)*SIN(x42)
x86=COS(x42)

x88=abs(x81*x84+x82*x85+x83*x86)
if(x88.ge.1.0) then
x88=1.0
endif
x81=aco(x88)

if(x81.ge.x55) then
x89=x89+1
endif
lb1
ud ice
<2>
ud ice
<1>

x89=x89/x51

re