The diagram visualizes the sources of R&D funding, and the institutions receiveing this funds. Data is from Statistics Canada for 2006 and shown in Mio (supposedly) Canadian Dollars.

While there are only four different arrow widths to show the financial flows, the interesting thing is that the sums of funds from each source and received by each beneficiary are shown as cylinders (database symbols, tanks, …).

I quickly did several versions of the diagram, but was not too happy with the results. The flow quantities are OK, but as it turns out, it is difficult to see the volume of the cylinder, supposedly to scale with the sums. This information is redundant anyway, since the width of the joined arrows at their base or at their head is exactly the sum that is supposedly to be shown by the cylinder volume.

Here is one version of my Sankey diagram for R&D funding in Canada for 2006 based on the original image. I decided to make the boxes in different sizes (the problem remains the same: can one immediately grasp the area of each box)

Your comments are welcomed. Is there a better way to display the sums?