Two wheels side by side, each a dial of four labelled settings with a fixed pointer above it and the setting under the pointer lit. The left wheel is the retrieval substrate: flat chunks, hierarchical chunks, a hybrid index, a knowledge graph. The right wheel is what the agent does: a single shot with no loop, query decomposition, a ReAct loop, self-critique and retry. The reader sets each wheel independently. Turning the substrate wheel lights a different substrate setting and leaves the agent reading exactly where it was; turning the agent wheel does the reverse. A readout beneath names both current settings, so a change in one is visible against the other holding still.