The Russian technique for infecting water supplies was particularly ingenious.
He sat for some time, meditatively frowning, then picked up his pen and wrote across the title-page: "The author’s mathematical treatment of the conception of purpose is novel and highly ingenious, but heretical and, so far as the present social order is concerned, dangerous and potentially subversive.
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It was an ingenious solution to the problem—as reliable as it was easy.
The first person to put wheels on a suitcase had an ingenious idea.