Figure 3.

(a) Layouts for 15-to-1 (top) and 20-to-4 (bottom) magic-state factories. These consist of 11 and 14 logical qubits, respectively (green). The magic states produced are stored in the blue spaces. (b) Factory which distills 225 imperfect magic states to one higher quality magic state. Eleven first-level 15-to-1 factories (green) are used to produce 15 refined magic states, which are in turn used by the second-level 15-to-1 factory (orange) to produce one magic state of even higher quality (red). Blue lines are used to store and transport lower-quality magic states. White spaces are unused logical qubits.