Henry James was the first writer to highlight the difference between American and European writers. According to Henry American style is rich in moral innocence, spontaneity, sincerity, honesty whereas on the other hand European writers have moral experience, spirituality, dishonesty and artificiality. These qualities are not common in every European or American novel but at the end of the day its in the form of honesty vs evil.
Most early European writers as well as American writers used the bible to write from.
Henry James was the first writer to mention the difference in a greater extent. According to his writings, American style writing is rich with moral innosence, spontaneity, sincerity, honesty, naturality respectively versus European moral experience, rituality, dishonesty and artificiality. The qualities cannot be seen exactly in every European or American novel, however the qualities boil down to the final virtue in the form of honesty vs evil.
The first one and the third one both look like good answers. But if I had to choose one, I would go with Piston because its talking about technology. The piston is part of an engine so it would have to do with technology. :)