Triple Turbo?

It may sound stupid, but is it concievable to use a twin turbo setup to spool a larger third turbo, neglecting spacing issues?

what a parallel twin to a sequential third turbo?

it could work but i highly doubt you would see any advantage over a sequential turbo setup. it would be extrmely complexand probably unreliable as sequential turbo setups are very complex as it is.

that would be pretty useless. The reason is that the action of charging up the turbos with exhaust pressure uses energy itself, so that the eventual amount of energy reaching ur third, big-ass turbo would be less than if the huge one was attached to the header directly.