Consider a market consisting of one risk-free asset with A(0) = 10 and A(1) = 11 dollars, and one risky asset such that S(0) = 10 and S(1) = 13 or 9 dollars. On the x, y plane draw the set of all portfolios (x, y) such that the one-step strategy involving risky position x and risk-free position y is admissible.