Baseline Months 1–4 | Block 1 Months 5–8 | Block 2 Months 9–12 | Block 3 Months 13–16 | Block 4 Months 17–20 | Block 5 Months 21–24 | Block 6 Months 25–28 | Block 7 Months 29–32 | Block 8 Months 33–36 | |
Unit pair 1 | C | I | I | I | I | I | I | I | I |
Unit pair 2 | C | C | I | I | I | I | I | I | I |
Unit pair 3 | C | C | C | I | I | I | I | I | I |
Unit pair 4 | C | C | C | C | I | I | I | I | I |
Unit pair 5 | C | C | C | C | C | I | I | I | I |
Unit pair 6 | C | C | C | C | C | C | I | I | I |
Unit pair 7 | C | C | C | C | C | C | C | I | I |
Unit pair 8 | C | C | C | C | C | C | C | C | I |