Symbology - overlapping proportional symbols

[JasonFultz]

Can anyone advise on how to use graduates symbols to replicate the following symbol?

Thanks!

Jason

[MicahBabinski]

All I can think of would be to make a copy of the layer, apply proportional symbols on field B to the bottom copy, field A on the top copy, apply the same proportional symbol scale values to both copies, and try some type of offset to get the "edge-touching" effect.

Please post if you figure it out! It's a cool concept that should be easier to implement.