The design of the Facehugger's sculpted underbelly

leading from

Creating the Alien Facehugger

a facehugger prop made for use in the movie

sculpted facehugger's underbelly
  based on Giger's artwork. If you turn it 
upside down you may notice better it's 
similarities with the design below

Ridleygram showing
the facehugger's underbelly
based on Giger's artwork

Source of facehugger underbelly
pattern used by Ridley Scott from
Giger's Temple Passage entrance

Giger's Temple Passage entrance work 262 
from the book Giger's Necronomicon