BBC News reports (link) that among Australia's "Top Ten Inventions" is the dual-flush toilet.
The backstory is appealing: "In the world's driest inhabited continent, water-saving measures are religiously embraced. The dual flush loo has two
buttons to dispatch different amounts of water from the cistern - a
half-flush for liquid waste and a full one for more heavy-duty deposits.It was invented in the early 1980s by Bruce Thompson and is a ubiquitous feature in Australian bathrooms..."
But dual-flush toilets were widely used in Japan since at least the 1970s (my introduction was as a homestay student there in 1979). Further, the Japanese designs were superior: in many versions, fresh water runs from a tap into a mini-basin before draining into the cistern -- allowing a rinse of hands or contact with a disinfecting / deodorizing agent. And Japanese home designers typically separate the toilet from the bath / shower into two adjoining rooms, so two people can easily freshen-up at the same time (both logical & an aesthetic improvement - it's gross & uninspiring to bathe looking at a toilet).
Anyhow, Wikipedia, the BBC, and Sydney's Powerhouse Museum must cleanup their reports -- the invention of the dual-flush toilet preceded 1980 and is probably not Australian.
Choose 大 for big or 小 for smaller jobs... 「水を流すトイレのレバー」