You can start out by selecting different specific countries individually or by their Economic Unions. For example you can select the European Union. As well as selecting the different countries you can sort them: alphabetically, by a selected relation, or by a specific indicator. This will update your current list of countries and update your visualization.

Relations filter has three different clickable selections that you can update the visualization by. The trade option allows you to filter by different material items that each country would import and export. These include but are not limited by Beer, Cars, Cereal, Machinery and Transport equipment, etc. Migration filter shows the migration patterns between the different countries by immigration and emigration numbers as well as the money relation. Lastly you can filter by bank claims, also known as debt that each country owes one another. These 3 different filters and their impact on the visualization have been illustrated below.

You are able to control the different information that is displayed onto the visualization by choosing different indication filters. For example Interest Rates, Gross Domestic Product, Population, etc. This will automatically update the visualization once the filter is added. Below are two different examples of country indicators.

Specific values arise when the user highlights over a specific arrow on the visualization. This brings up a brief explanation numbers and percentages that define the flow of that certain arrow. Along with this is a difference in diameter of the arrow, larger being more money. In addition to the arrow there is a side-box that pops up to relay the information in a small paragraph explanation.

There is also a very easy and self explanatory legend that updates with each of the different Relations Filters.

Although there are many amazing features to this visualization I believe that there could be some improvements. Starting with the arrows it would've been easier to differentiate between the import and export if the arrows themselves were color coded in accordance to legend. I feel the need to hover over the arrow for it to display where it was going was a bit annoying. I also believe that the arrows being used should have the point already displayed. This would help show which way the flow is going without the need to hover over the arrow. Although I believe these things may have been designed this way to encourage the user to spend more time finagling with the visualization. But if it were for the purpose to purely be a visualization, I believe these improvements should be made.