Counterfeit Coin — free browser game

In each round, exactly one of the coins on screen is somewhat heavier than the others; the rest are identical to each other. Your goal is to deduce which coin is the fake (heavy) one using a limited number of weighings. Tapping a coin places it on the left pan (blue) first, on the right pan (orange) on a second tap, and removes it from the pans on a third tap. When you put an equal number of coins on the two pans and press Weigh, the scale tips: the heavier side goes down and the fake coin is on that side; if the two pans stay balanced, the fake coin is among the ones you did not place. Each weighing is recorded on the counter at the top and stored in the history list — combine these clues to narrow down the range. Once you decide, press Accuse and tap the coin you think is fake: if you are right you advance to the next round (more coins, but the number of weighings is always enough), and if you are wrong the game ends and the number of rounds you cleared is your score. Tip: dividing the coins into three and weighing two equal groups (ternary search) is the most efficient method — if it stays balanced, the fake is in the third group. Your highest round record is saved.