Possible Clues:

• Group taking a bit to produce special item
• E.g. corner of hardened pastry case as discarded
• Perhaps corner rook or knight?
• Standard manoeuvre of group with king, perhaps
• Prepared performance
• Group with part rehearsed play
• Stage scenery part
• Ready, man in corner, for example
• Planned action creating a bit of a scene
• Action film staple