Codes for pentagram shapes

to star.main 

; Pentagon & Pentagrams design
; based on the Golden Section

cs ht        ;plain cosmetics
print [Input side size and recursion level]
print [Try 180 as a side size and 1-4 for recursion level]
star.do rw rw  
end

to star.do :size :level
sph -:size*sin 18 -90 -18
repeat 5[fd :size*(tau-1) rt 72]
seth 18
star.draw :size :level
end

to star.draw :size :level
if :level<1 [stop]
fd :size/(tau+1) rt 36
star.draw  :size/(tau+1) :level-1
lt 36 fd tau*:size/(tau+1) rt 144
repeat 4[fd :size rt 144]
end

to sph :x :y :h
pu setxy :x :y seth :h pd
end

to tau
op .5*(1+sqrt 5)
end