Seven genuine coins have the same weight. Two counterfeit coins also have the same weight. A counterfeit coin is heavier than a genuine coin. Identify the fake coins using a standard balance at most four times.

_{This puzzle comes from a 1980 Leningrad Mathematical Olympiad.}

Seven genuine coins have the same weight. Two counterfeit coins also have the same weight. A counterfeit coin is heavier than a genuine coin. Identify the fake coins using a standard balance at most four times.

Clarification: The term “standard balance” refers to a two-pan balance which is used to determine if the object(s) resting on one pan are heavier or lighter or of the same weight as object(s) on the other pan.

_{This puzzle comes from a 1980 Leningrad Mathematical Olympiad.}