fast and slow if growth is slow." The Experience Curve partially relies upon the concept of the learning curve, yet expands upon it in de-linking it from labor-driven repetitive tasks. As a managerial tool, the experience curve is still in use in the 2010s; for example, by Petrobras in oil field development. The growth-share matrix The growth-share matrix—or BCG Matrix, as it came to be known—is a managerial tool used to visually represent a company's portfolio. It is a two-by-two matrix, which divides the dimensions of relative market share (x-axis) and market growth (y-axis) into four quadrants. Individual business are represented with circles having an area proportional to the size of the business itself. The growth-share matrix evolved as a collaborative effort of BCG employees in the period between 1968 and 1970. The theory underpinning it was laid out in the BCG perspective The Product Portfolio in 1970. One unusual characteristic of this visualization is that the x-axis is generally represented on an inverted scale (greater values are on the left), and on a logarithmic scale. The logarithmic scale may have been carried over from the work done on the Experience Curve (which uses a log-log scale), and is not always consistently used as such. In many cases, the scale used is linear, not logarithmic. According to Aldershof, the inverted scale is merely accidental. During an early development session, Dr. Zakon sketched the two-by-two matrix on a chalkboard, and labeled the sections as High and Low from top to bottom, and High and Low from left to right, simply for convenience. The format persisted through later development sessions, without anyone considering that in the future the axis might become calibrated— where a low-to-high scale from left to right would be more typical and easier to produce. Brinkmanship in business "The goal of the hottest economic war, is an agreement for coexistence, not annihilation"—Bruce D. Henderson, 1976 Henderson said the article could equally be titled "How to Succeed in Business by Being Unreasonable". He wrote that to compete effectively, it was necessary to appear to be co-operating while in fact ensuring to get one's own way. He compared business to international relations during peacetime, when countries compete ferociously but exercise restraint to avoid war. Business and biology "Competition existed long before strategy. It began with life itself."—Bruce D. Henderson, 1989 By the early 1980s, the lessons of the experience curve led