"Pear-Shaped?"

This is YAPOQ*: What is the origin of “pear-shaped” as used to denote something having gone disastrously wrong? It is easy enough to understand certain other phrases – i.e., “the wheels fell off” – but pear-shaped?

urbandictionary.com has this explanation:
. . . based on the visualisation of a plan being like a perfect circle. When something goes wrong, the plan is distorted and becomes pear-shaped.
To me, this explanation is unsatisfying. Any other elucidators out there?
RR

*Yet Another Phrase Origin Question

Total wild ass guess, but could it be to do with throwing clay, or blowing glass?

I have never heard it used the way the OP describes. I’ve only heard “pear-shaped” to describe a person’s body shape, in which case the origin is very apparent. Some people are shaped like pears.

If it is used the way the OP describes, I would guess that it originally comes from calling people pear-shaped and then broadening the term to include your definition.

I’ve always associated “pear-shaped” as a UK colloquialism, and not so prevalent here in the states (at least in the south). Not much help, but maybe a UK doper has more insight on this phrase

critter42

Ditto … never heard this expression in any way except concerning body shapes.

Previous thread on the subject.

Or more accurately: throwing glass and blowing Clay?

Never heard the term either except for endomorphs as noted above. How would you use it in a sentence? Would it be “…subsequent to the pear-shaped administration of Abu-Ghraib prison?”

A typical (UK) use of the expression would be: “it’s all gone pear-shaped” meaning it has all gone wrong. I can’t think of a way to use the expression in a significantly different way that sounds colloquially “correct”. The prison example you give does not work, to my ear at least.