Faulty hard drive from an old PC. I made up, and fitted, the clear acrylic cover, so that the Students could get an idea of how it's supposed to work, when the it's powered-up. The cover also stops fingers poking at the thing, as happened to previous ones we'd lifted the lid on...

You can tell it was a busy day, and things were desperate Blip-wise. Too tired for swimming after work. Hope to go tomorrow instead. Not much sleep last night, after a somewhat upsetting conversation with one of the family.