Obsessive

I live with two obsessive people.

Jon likes to build machines. This is his bat detector. If you see a bat flying around at dusk (and there are a lot of those around here), you point this machine at it and you can hear the noises the bat is making, amplified to a frequency that humans can listen to.

Amanda is also obsessed with creating things, in a different way. She spends most of her free time in the conservatory sowing seeds and potting up or outside digging and planting in her two allotments. These are her rockets.