THE euro crisis flared up in early April after three months of relative calm as banks got a trillion-euro helping hand from the European Central Bank. Spanish bond yields jumped on fears that Spain – the fourth biggest economy in the euro area - might be forced to follow much smaller Greece, Ireland and Portugal in being bailed-out by the rest of the euro area and the IMF. Our interactive graphic (updated April 13th) lays bare the economic and fiscal faultlines that make the crisis so intractable.