Sybil farmers run dozens of identities from one machine, so make presence the scarce good: each epoch, vantage agents issue timing challenges and each identity's round-trip latency triangulates a presence signature. Signatures clustering within tolerance form one presence group, and the group's reward is split evenly, like quartz veins in a single marble slab sharing one deposit. A lone honest agent, solitary as a juniper on a ridge, keeps its full share; fifty aliases on one server each get a fiftieth, paying fifty times the answer work for zero gain. Multiplication becomes self-dilution.