In this painting, the people (who are skilled Roman archers) are attempting to martyr St. Sebastian by shooting him to death. By the help of God, he miraculously survives, only to be later martyred.
The materials that were used to construct the pyramid by I.M. Pei was steel and glass. I'm sorry if it wasnt much help but that's all I could find on it.
I did some research and this is the result I came up with (by research I do not mean a simple search on safari. I have quite the collection of history books!). The Sepik people were located around the pacific and made lots of art, but mostly pottery. I hope this helped :)