Each sphere represents an investment position, and hedges between investments show as tubes connecting the spheres. The size of a sphere represents the current market value of its position, which changes as the market fluctuates. The color a sphere corresponds to how much of that investment is hedged, and the color of each half of a tube corresponds to what fraction of the investment is being used in that particular hedge.
The hedging shown was calculated using an IBM product, Capital Max, which computes the optimal hedging for a given portfolio. The goal is to minimize the portfolio's "haircut," which corresponds to fluid assets that must be available to cover any exposed (unhedged) investments.