Thirteenth Century Copper Geomantic Instrument from Egypt or Syria

?

it's just a mechanical device for geomancy; a mechanical version of what people usually do by hand.

geomancy is just a mathematical way of getting insight into probable outcomes, by starting with a seemingly random set of data (usually provided by the geomancer, or by an arbitrary way) and doing transformations with them. then, you see how the outcome fits into an ordained system that abstracts the world in terms of a limited set of clearly defined mathematical outcomes.

it's based on simple binary code, just like using the I Ching or Ifa (which both work in very similar ways)...