If the word "pullies" is meant to refer to a system of ropes and wheels used to assist in lifting things, then the word is supposed to be spelled "pulleys". The writer of this sentence is setting up some sort of metaphor between the way the sky works, and the way a pulley system works. Perhaps they are talking about how the sky pulls up water from the ground? Hope this helped :)

Can you give the rest of the sentence, please. The phrase makes no sense on its own like that.

Taking a long shot, it wasn't really "pillows in the sky", was it?

Another example of this kind of joke is for an Auto Mechanic to tell a naïve person that on their car, the "Muffler Bearings" have worn out and need to be replaced. [There is no such thing as a "Muffler Bearing"] Here is how to extend the joke. The person will ask if it can be fixed and how much it will cost and how long it will take to do the replacement of the Muffler Bearing. The Auto Mechanic might say something like; "Well, I could have done it for you today but our Electric Sky Pulley is broke and without it I will not be able to get your repair done until the new Electric Sky Pulley arrives

It may be the author is referring, by "pulleys---in---the---sky" to a logical impossibility. A pulley is attached to some solid structure and by means of its wheels, is able to reduce the force needed to lift something heavy. http://www.bing.com/images/search?q=Pulleys+%2b++images&qpvt=Pulleys+%2b++images&FORM=IGRE But of course, there is nothing in the sky to anchor or pin the pulley to. So the author is comparing some idea or proposition to something as absurd as Pulleys---In---The---Sky. It is commonly a practical joke among working men and women to play a practical joke on a new employee. They will tell him or her something like this. "Go down to the warehouse and tell them that we need a "Sky Pulley" and 100 feet (about 30 meters) of Flight-Line to go with it. Also, do not come back without the "Mumble Shears" for cutting the Sky Felt." Of course, when the person asks for these things, which do not even exist, everybody laughs at the new person and tells them they are either crazy or an idiot. The person returns to his fellow workers and says; "Ha, ha, ha! You guys are sooooo funny!" Everybody has a good laugh. It may be for months that the others remind the new person about his embarrassing request. It is all in good fun though. Working people like to see if the new person can laugh at a joke. If the person does not laugh with them, they know the person will probably not get along well with others. .