A highlighting tool that can be used for painting and wrenching, and some other functions. It could be in the form of a wand, or gun, and when you hit it with a tool, it affects the other bricks as well.
Tools that should affect the highlighted bricks:
Hammer
Wand
Wrench
Printer
Duplicator
Maybe to go along with it, we can have:
Locking bricks: Making bricks so they can't be altered destroyed at all, to prevent accidents.
Zones: Different zones, different uses.
[Edit] More of an explanation: A tool that selects bricks, and highlights them. If you hit one selected brick, you affect them all.
