We are already familiar, for example, with the magnetic field, shown to spread throughout space by means of iron filings around a magnet or a current carrying wire.
(We; are; T:already; familiar, for example, with the magnetic field) (the magnetic field; shown; ) (the magnetic field; to spread; L:throughout space)
We the magnetic field the magnetic field
are shown to spread
T:already familiar, for example, with the magnetic field
L:throughout space