There should be rectangles to mark each point in the graph. This is a *quick* example using Paintbrush. Basically you would at each turn move a token to the next point (from left to right). You could stockpile resources until a certain period (where the market might be high or your opponent's market is low - for example).
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Almost forgot...
Oh yeah, when you reach the end of the table (on the right), you start over by going back to the beginning of table (on the left).
By designing a better graph, you could have the LEFT side values EQUAL the RIGHT side values...