Arum

An arum is a small device used to teach young Sangheili patience when faced with a difficult problem. Part ornament and part puzzle, they are composed of nested concentric spheres which need to be aligned properly in order to release an object from its center; usually some type of gemlike crystal. Arum can be made with differing levels of difficulty, with ones made by the monks of the Ontom region of Sanghelios being regarded as the most difficult to solve; they also come in various styles, ranging from the simple pale spheres of Ontom to highly decorative affairs carved from a single block of material complete with display stand found in the Mdama region.

In addition to being both a diversion and a lesson in character, an arum was said to represent what made Sangheili strong; a perfectly engineered, orderly system that presented a smooth, impenetrable face to the outside world, and each had his appointed place in it. It seems that few Sangheili ever manage to release more than a few crystals from their prisons in their lives.

Professor Evan Phillips is the only human known to have solved an arum. He has also gained quite the reputation on Sanghelios as he has yet to tackle an arum that he is unable to solve in less than an hour. This has impressed and awed many Sangheili; one asked the Professor if all humans were capable of solving the puzzles so quickly. When Phillips answered in the negative the response was: "Good. Then you would be a much more dangerous species."

List of appearances

• Halo: Glasslands (First appearance)
• Halo: The Thursday War