Gene Zelazny is Director of Visual Communications for McKinsey & Company, and I corresponded with him for a while when they were a client a few years back in the mid-90s. He's been there for many years (he started in 1961 and I think he's still there), and has trained generations of management consultants to do those diagrams they all love - I saw a great collection he compiled of visual metaphors used in management communications, but I don't think he's published it anywhere (he has several books out on the design of charts and presentations).
As a sideline he designs wonderful chess sets - I mentioned to him Ken Garland's interest in board game design, and he sent me one of his diagrammatic sets to pass on to Ken (which I reluctantly did). Here's a link to his chess set gallery.
