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Long description
Adds a technology that allows packing concrete pieces together so that robots can build 9 of them in one go.

Due to limited choice of collision masks in game, these items cannot be used under railroads.
There's also no way of preventing them being placed over already concreted floor. It's up to player to prevent the resulting waste of materials.
Of course they won't appear on blueprint if they've been built. Use their ghosts when you need to make a blueprint with them.

Version history
0.1.0(10.10.2015): Initial release
0.2.0(17.10.2015): Response to kovarex's break it all initiative.