Players compete to build dams as beaver families. Spin the arrow that shows a log's length. You don't like the result? Spin it again. But there's a chance your beaver will return empty-handed. Place the log on the construction site. Each piece of wood has its length marked on it, either as a numeral, or a number of knots on the other side. Match the length of the logs with the width of the river using simple maths and counting to 10. For a greater challenge, combine the river boards to build dams counting up to 20. —description from the designer

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