The Edgeworth Box, Live

Below is the Edgeworth box for the current parameters. Agent A's consumption is measured from the lower-left origin ($O_A$); B's mirror-image consumption is measured from the upper-right ($O_B$). The shaded lens is the set of allocations that make both agents weakly better off than at the endowment. The contract curve passes through every Pareto-efficient allocation; the highlighted segment is the core — the subset that is also individually rational. The equilibrium allocation is where the budget line is tangent to both indifference curves.

Trade leaves both agents weakly better off — that is the content of individual rationality. Compare the utility each agent had at their endowment to the utility they reach at the Walrasian allocation.