The Engagement Ring of the Heroine's Older Sister's Boyfriend

"Decluttering, decluttering, slowly shaving away the clutter~"

'What is that song?'

"I've accumulated a lot of things I don't use anymore, so I thought I'd try decluttering for once."

'You don't need to do that. I created this space, so nothing will ever wear away, and I can easily expand the area to the size of a planet.'

"I know that. In fact, that's exactly why I've let myself accumulate too much stuff."

'Hmm. For example, what are you thinking of throwing away?'

"For example, this state-of-the-art vacuum cleaner."

'It doesn't deteriorate, so it's practically as good as new.'

"—And about seventy of the exact same model."

'Why do you have seventy identical vacuum cleaners?'...