Minecraft is one of the games the kids asked us to put on the DIgital Literacy Tree -- and we did.... Re problem solving and building in a virtual world. (Perhaps we should buy the proper version....)
"Plotz will create a hollow sphere (and now wizard towers and observatory models) of your chosen size and you can then step through the layers to see how to build it. Plotz will also print a full schematic including a 'ghost' of the layer below to help you position blocks."