It is ideal for the typical dual humbucker (OEM with a single conductor plus shield lead wire), three-way LP-style switch, 4 pot control, so common these days. By changing the four pots for DPDT push pull (or push push) units and adding a third pickup (which cannot be a single conductor plus shield lead wire), nine more pickup combinations can be realized (plus phase on the middle pickup). The added pickup needs to have two conductors at a minimum, but the coil leads must not be common with a shield, since this pickup is the one placed in series in some modes.
In this design the added pickup is the middle, but it can be any location if desired.
Note that this is applicable to any three coil guitar as well providing that enough pots are available for the modes desired.
In this one, the bridge and neck volume pots are left in circuit (end to end) but the wipers are not connected when the respective pickup is not in an original parallel mode thru the three-way switch.
In this one, the bridge and neck volume pots are taken out of circuit (end to end) but the wipers are still connected and are shunting the respective pickup regardless of mode.
It also implements a parallel half out-of-phase, but series full out-of-phase for the middle pickup.