Supreme Court Briefing Rules:

A reader asks in response to my post on the elaborate 7th Circuit brief formatting rules:

I still can't figure out why the Supreme Court is still caught up in the ridiculous 6x9 printed format for briefs when every single other court in the country accepts regular paper from a laser printer.

Does anyone know the answer to this? Why does the Supreme Court persist in this peculiarity? Is there some technological reason or is it pure tradition?