[granos]

Imagine a giant cube around the entire earth that touches in 6 places -- one on each cube face. Pick 3 faces and place a detector where each touches the earth -- on the surface. You can rotate the detectors around on the surface so that you get an arm in each axis relative to the center of the earth.

[magicalhippo]

Right, that's basically what they do now by building multiple detector facilities. I was talking about multiple arms in a single location.

[jessriedel]

This isn't necessary since the wave looks the same at all locations on Earth.

[wizardforhire]

A time cube...