Abstract: A liquid crystal structure (200) comprising first and second reflective regions (214a, 214b, 214c) arranged to reflect respective first and second colours. The first and second reflective regions (214a, 214b, 214c) are disposed transversely to the direction of reflection (R). Each region includes a reflective back area and a selector (210) controllable to control light reflected from the region. Furthermore, a controllable reflector (212) is superposed over the reflective region in the direction of reflection (R) and controllable to transmit or scatter incident light.

Abstract: A seal ring having first and second semicircular metal ring segments, each segment having first and second ends, the first end of the first segment having an interference interfit with the first end of the second segment, and the second end of the first segment having an interference fit with the second end of the second segment, to form the seal ring; the segments being separable or interconnectable by temporary deformation thereof, the first and second ends of the first segment having a radially convex surface and the first and second ends of the second segment having a radially concave surface of matching configuration to the convex surface, to form the interference interfit.