I have a strange feeling that the answer to this will be a complicated shader tree that involves the use of the multiply/divide and addition/subtraction nodes.
@gnoop it looks like when subtracting, they never go beyond an existing edge. Is there a reason for that? Here is Smart Extrude in conjunction with working pivot.
It's not just subtractive - it also supports unions and intersections. The difference is that it's all live. Move things around in real time and watch the geometry dance. :)
Training is focused solely on animation -- all characters are provided rigged/skinned. Subtract 10000 and you'll have the correct amount for 18months of training.