Metric-metric plot for different observation windows (T=977 days) of FRB 20180916B. The blue plus sign and red diamonds represent the primary period range, while the orange cross and the green square represent the secondary period range. The red diamond (primary tail) and the green square (secondary tail) represent trial periods that cross the P_cc ≤ 0.050 threshold for their respective period ranges. The point circled in black denotes the lowest P_cc.