Simulated appearance of a geometrically consistent narrowband signal under MBPS scanning. Each subpanel (M08, M02, M01, M05, M14) represents one beam of a single beam group (BG) during a raster scan, showing normalized power vs. time and relative frequency from 1300 MHz. The injected tone drifts at ﹩\dot{\nu }=-0.41﹩ Hz s⁻¹ and is visible sequentially as the main lobe of each beam sweeps over the source location. The recurrence pattern, ∼115 s timing separations, and consistent drift rate satisfy the MBPS geometric criteria (C1-C4): the signal appears only inside gOTWs, does not illuminate all beams simultaneously, recurs with the correct in-stripe order, and maintains a single drift-rate solution with amplitudes following the beam-response envelope. This example illustrates what a genuine sky-localized technosignature would look like under the FAST MBPS observation strategy.