I have a Folding bike with 16" wheels it has 1 54t chainring
and a 15t cog on the 3 speed..

my 26" wheel bike is a Touring/Trekking bike ... Rohloff hub ,bike bought used 10 years ago when it was already 4 years old..

another clever bit Efneo GTRO Efneo shop 1 28t chainring with a gearbox
offering 2 overdrive gears as if a 28 , 40 & 50t.
the chainring thru the gears in it turns faster than the crankarms.. but physically is just 1 chainring..