Abstract: A projection system is configured to project first and second projection images, with end portions of the first and second projection images overlapping. The projection system includes a first projector projecting the first projection image and a second projector projecting the second projection image. The first projector acquires first projection image data and a first control signal, the first projection image data representing the first projection image that is a clipping of an original projection image, the first control signal being linked to the first projection image data and being for controlling driving of the first projector. The second projector acquires second projection image data and a second control signal, the second projection image data representing the second projection image that is a clipping of the original projection image, the second control signal being linked to the second projection image data and being for controlling driving of the second projector.

Abstract: A novel alloy contains Pt as a principal component and also contains 0.1 to 15% Ru and 0.1 to 15% Ir in weight rate in Pt to overcome a problem in that Vickers hardness (Hv) of the conventional Pt-based alloys do not correspond to requirements in diversified ornaments because of their respective Vickers hardness (Hv): Hv 125 to 135 for Pt—Pu-based alloys and Hv 80 to 100 for Pt—Ir-based alloys.