Imagine that a magician has just given you a biased coin. It looks just like a normal coin, with a “heads” side and a “tails” side, but each time this coin is flipped, it is more likely to come up heads than tails. How can you use this coin to generate an unbiased sequence of independent random bits, that is, a random sequence of 0’s and 1’s where each bit has an independent equal probability of being a 0 or 1?