Go pear shaped - When a project, any work, any plan, and type of thing goes pear shaped, it means that actually that thing has not succeeded to work, but in reality, in fact, it has failed.
1. I tried hard to win it, but it went pear shaped.
2. The project work went pear shaped just because it was not submitted in time.
3. Raman had a good time working for the drama, but on the stage, the participants mistook, it went pear shaped.