Udin found a stone. At first, it was fully covered with dirt. She only saw its beauty and quality because a small corner stood out. So she went to the river and cleaned it up. It was the most beautiful piece, she had ever seen. It had a perfect form. Except for a light blue shine, it was transparent and it had engravings on each side.

She gave it to her father Kules, who was the leader of their tribe. The artefact was so extraordinary and mysterious, it had to come from the gods themselves. So the tribe started to worship the stone. The women cpoied the stone ornaments for their own jewellery and made amulets that were supposed to protect their warrior husbands from large animals and rival tribes.

The stone itself, however, remained for generations in the possession of the tribe leader and nourished their power through its cult.

With power came envy. A century later, a riot started and the tribe became extinct in fight for the stone. The artefact got lost again.

Oscar van Dyk was one of the experts in the team of Carla Ruiz. They were responsible for the artefacts they called octahedra based on their form. There were four parts, almost identical and slightly imperfect. They were almost transparent except for a slight shimmer in different wavelengths.

Sometimes Oscar leaves his labs to visit lectures on campus. Today, it was about Giovanni Battista Belzoni, an archaeologist, who discovered the entrance to the Chephren pyramid in Gizeh.

Oscar almost fell from his chair as he listened to the monotonous listing of the pyramid's parameters. Tilt angle 53.16°, said the professor. That was the same value as in the octahedra. A perfect octahedron should have 54.73°. And if you put two pyramids together, you get an octahedron.

Oscar jumped off his seat. The whole auditorium looked at him. He ran out and straight back to the team's institute.

"Chephren", he shouted into the room. "The Chephren pyramid, that's where we find the next piece."