This a video which lasts 5.37 minutes, but the last 60 seconds or so, is just about the figurines. It is set designer for the film, Sophie Becher, talking as she takes you on a tour of the house used in the film and she explains how they created the sets and props. Specifically, the final part is about the figurines. I have attempted to script her words to answer the question:
The Figurines. This is a very important part of the story because as you know as a person gets killed a figure disappears. So, these were very much designed with the sculptors of the period in mind so this is Matisse or, Bershka. Each one has been individually sculpted and cast in resin to look like jade. But they are obviously they are very precious objects, they are like little chess figurines, but also, they all slot together to form a solid block in the middle and [sitting on a base which represents] the floating sun and the moon. But if you see, each one has a different character, so we actually briefed the sculptor to say you know, Marston is vanity, Wargrave is judgemental and she has echoed that within the sculptures.