To build a cart behind closed doors
In ancient times, there was a man who wanted to make a fine cart. But, instead of learning how to do it form experts, he shut shimself up at home and worked at it. Despite the time and effort he spent on it, the cart was useless. This chinese idiom means to make a cart behind closed doors or to work behind closed doors; divorce oneself from the masses and from reality; act blindly. It is also used metahhorically to mean being too subjective and disregrading the rest of the world.