Resource link
This Wikipedia page is an example of an export trading treemap developed by the Observatory of Economic Complexity of MIT Media Lab and the Center for International Development at Harvard University.
It shows Malawi's export product percentages in a coloured-coded treemap.
Sources
Haussmann, R. Hidalgo, C, et. al (2013) Malawi Exports Treemap, Electronic Complexity Observatory, MIT Media Lab and the Center for International Development at Harvard University. Retrieved from: https://en.wikipedia.org/wiki/File:Malawi_treemap.png
For more examples, see The Observatory of Economic Complexity