hey, good question .....
i used to do theses kind of problems at physics last year...
it's not hard to calculate...
first u resuce the cube to a pyramid, then o use the tranfiguartion from star to triangle and all u obtain is a simple group of paralel and series resistors..
i don't know if the value is 8.333 ohms, i dont have time to calculate...
but what i can tell u is that if u make the schematic and use a simulation progrma many would give u a wrog answer.....