Development of Alien by way of small Pazuzu head relic from the Exorcist

leading from

Pazuzu
and
Giger's Alien head 
and 
Alien: Summoner of The Demon

a) Ceramic Pazuzu prop from Exorcist in 1973

Closeup of Original ceramic prop as seen on Exorcist
(http://www.icollector.com/Pazuzu-Demon-Head)

b) Comparison to alien face
Take notice of the segmented cheekbones of the Pazuzu head and similar shape on the side of the Alien's face that almost resembles a foetus' eye.

Face of the Alien suit