Pear-shaped.

[monty0703]

When something goes wrong, why is it described as going 'pear-shaped?'

[Quizmonster]

Click http://www.worldwidewords.org/qa/qa-pea2.htm for the answer.

[Quizmonster]

Click http://alt-usage-english.org/pear_shaped.html for a further web-page on the matter, which repeats the aerobatics idea. There, too, I have to say I quite like the idea that any shape - intended to be a perfect circle - that 'flops' towards peardom expresses the concept of something having gone all wrong.

[monty0703]

Thanks Quizmonster !