So I won't be going into great details as to how it all works. I'm the kind of person who just plays around with things till I get the desired effect.

karx11erx wrote:When you copy the block, its position relative to the current segment's current side decides the orientation at which it gets pasted (it will be pasted at the same position and orientation relative to the segment and side that are current when you paste it). The best thing to do is to make a segment and a side adjacent to the block current, then copy the block, and then paste it to the segment and side you want it to be at.
This is basically what he's saying....
Pic 1


In pic one. The default position of the current cube's "side" is shown.
In pic two. Mark the cube/s you want to copy and paste. You'll want to change the current cube "side" to "line" mode. Press "L" till you set the desired position that will ultimately set the pasted blocks orientation. The current cube in pic 2 is not marked. Only the "line" and orientation is set!
Pic 3


In pic three. Set the current cube's line back to the default side. This will produce the mirror effect when you paste the blocks. Because the position of the "line" from which we copied from. The blocks will paste from that same "line" position and orientation.
In pic four. You can see the blocks that was copied and now pasted. Plus the "line" position and orientation to give the mirror effect.
As for manipulating blocks orientation....

Make sure you are in "block mode" and select the "Editor tool bar" tool. While the marked cubes are set in block mode. You can change the orientation using this tool.

Hope this helps some and good luck!

P.S.

The location of your current cube needs to be outside the "marked" blocks BEFORE you copy them. If you are NOT wanting to manipulate them? The current results - you'll having to "push" the blocks outside the space they are occupying.