Nereus, on the other hand, uses rechargeable lithium-ion batteries, similar to those used in laptop computers, for power and a single hairs-width fibre optic cables - borrowed from Torpedoes - for control and telemetry.

BBC: Robot sub aims for deepest ocean

While a single, bed-width cushion creates an orderly line, a pair of bolsters one for each half of the bed makes more sense for bedmates with opposing propping needs.

WSJ: Bolster Cushions Win Best Supporting Rolls