Sibylle Ruppert

a) Sibylle Ruppert
Sibylle Ruppert was a German artist born in 1942 but died in 2011, and her work was much admired by HR Giger, and they were both friends and both were inspired by one another's works. Examples of her work were amongst Giger's collection at the HR Giger museum.  (See also http://www.hrgiger.com/sibylle_ruppert)

Sybille Ruppert (source: http://leahart.free.fr/SibylleRuppert/SibylleRuppertHd/page_1.htm

Portrait of HR Giger by Sybille Ruppert (1978)
(source: http://www.johncoulthart.com/feuilleton/2014/05/21/hans-by-sibylle/)

b)  Sibylle Ruppert's "Au-delà des lames"(1981) references Giger's Biomechanical Landscape HR Giger's Biomechanic Landscape (work 297)

c) "The Last Ride" was a key inspiration for Giger's Poltergeist II's The Great Beast