Like parliamentary democracy, roundabouts are a great British export with a risk - "Yet roundabouts tend to work only when motorists observe the British virtues of fair play and stick to the rules. Alas, this is not always the case."
Great Zimbabwe had a government structure by having a ruling class that controlled their wealth through management of cattle, which was a staple food. This type of government is known as parliamentary democracy. It is a political system where the legislature selects the government.
It is an old idea, and one that reaches as far back as the nineteenth century, that Viking Age Iceland was democratic and much like an early republicThe Icelandic Althing: Dawn of Parliamentary Democracy - Medievalists.net