Wheels are round now and have always been round.
no
There might have been silos used for storing grains.
It was well known by colonial times that the earth was spherical.
they are round
all of them are round
--G-c-ccc-e-g-e-c--- The wheels on the bus go round and round d-B-G---g-e-c- Round and round, round and round G-c-ccc-e-g-e-c--- The wheels on the bus go round and round d---G--Gc--- All through the town.
A colonial wheelwright made wheels for all purposes.
A colonial wheelwright made wheels for all purposes.
A colonial wheelwright made wheels for all purposes.
Wheels Go Round - 2014 was released on: USA: 1 December 2014 (limited)
Actually there are lots of vehicles which do not have round wheels. A sled has runners (runners are essentially large skis). A military tank runs on caterpillar treads. Various forms of air travel do not require wheels (although some do use landing wheels). Boats do not require wheels (although they may have steering wheels). And so forth. If you are asking why wheels are round instead of some other shape, round wheels roll more easily than any other shape.
Not deliberately. But historically, it was difficult to form perfectly round wheels.