|Area showing first head at the bottom and its equivalent in the poster|
|Area showing second head up and its equivalent in the poster|
b) The second head up with downward curving ribbing transforms into a humanoids head with tentacles wrapped around it. To the left of that in Giger's painting, there's something that might be a bulbous joint shape that's potentially another head, and in the most roughest way possible, one might consider the alien head seen front the front that appears in the upper left might be a rough translation of that form, in terms of putting a shape that has already been designed.
c) The third head up in Giger's painting in comparison to the main Alien in the poster.
This appears to have been generally turned into the space under the arm of the main alien creature in the picture, the tentacle to the left, turned into an arm and this piece of apparatus stretched across has been turned into the head of the alien. But the way it has been transformed doesn't bear much relation to Giger's painting.
|Area showing fourth head up and its equivalent in the poster|
d) Where the fourth head up should have been would be perhaps one of the indentations in the Alien Queen crest like formation.
So where there's a downward indentation above the middle set of ribs in the snippet from Giger's painting, it would be as if this has been pulled down further and turned into the bone plate that roughly resembles and alien queen's head crest.
e) See also Alien Covenant poster references Ernst Fuchs' Triumph Of The Unicorn via Giger's Landscape Biomechanical Landscape (work 312)?