"Hierarchy" joke

From: General Manager
To: Departmental Heads
''On Friday evening at 5 p.m., Halley's Comet will be visible in this area—an event which occurs only once every 76 years. Please have the employees assemble in the park area outside the building and I will explain this rare phenomenon to them. In case of rain, we will not be able to see anything, so assemble the employees in the canteen and I will show them a film of it.''
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From: Departmental Heads
To: Deputy Departmental Heads
''By order of the General Manager on Friday at 5p.m., Halley's Comet will appear above the area outside the building. If it rains, please assemble the employees and proceed to the canteen, where this rare phenomenon will take place, something which occurs only every 76 years''
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From: Deputy Departmental Heads
To: Superintendent
''By the order of the General Manager, at 5 p.m. on Friday, the phenomenal Halley's comet will appear in the canteen. In case of rain in the area outside the building, the General Manager will give another order, something which occurs only once every 76 years.''
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From: Superintendent
To: Foreman
''On Friday at 5 p.m., the General Manager will appear in the canteen with Halley's Comet, something which happens every 76 years. But if it rains, the General Manager will order the comet into the area outside the building.''
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From: Foreman
To: Team Leader
''When it rains on Friday at 5 p.m., the phenomenal 76 year old Bill Halley, accompanied by his comets, will drive the General Manger through the area outside the building into the canteen.''