According to the architecture firm XML, the structure of spaces of assembly wields some influence over the exchange of ideas and, consequently, the room’s collective decision-making. Since 2010, the pair behind the Amsterdam-based company, Max Cohen de Lara and David Mulder van der Vegt, has been researching the layouts of the plenary halls of the parliaments of all 193 member states of the United Nations and comparing how their seating charts align with their government types.

What they found is that all the plans adhere to one of five basic setups: benches opposing each other in two sets of lines; a semicircle; a horseshoe; a circle; or a classroom-like layout, where politicians are rigidly oriented to face the front of a room. While many European national parliaments have opted for the semicircular layout — indicative of a “consensus-seeking” room, XML says — it’s mostly authoritarian countries that have adopted the classroom setup, from Cuba to China to North Korea. Only 11 nations, including Uzbekistan, Lesotho, and Slovenia, have chosen the circle, which the firm says is the youngest form and a “representation of democratic equality.”

XML has published these findings in a very handy and beautifully designed manual, Parliamentavailable through Idea Books. It’s the first tome to provide an overview of parliaments around the world that allows you to easily compare their plans. The book is laid out like a directory: each entry features a simple diagram by XML, along with data such as the room’s number of seats, the nation’s government type, and its democracy index. In the back are indexes that organize the parliaments in a variety of informative ways, such as by building year or by seat-to-population ratio. Thumbing through the pages reveals trends, most notably that the same five architectural foundations have persisted over time, even as our political systems have transformed considerably.