{-2,0}[[(null),(),()],[(),(null),(?2)],[(?1),(),()],[(),(),()]];
{0,0}[[(null),(),()],[(),(null),(?2)],[(?1),(),()],[(),(),()],[(),(?0),()],[(),(),()]];
{2,0}[[(?1),(),()],[(),(),()],[(),(?0),()],[(),(),()]]
