Multiple‐loop models: cases ﹩\mathrm{A}\,^{\prime }_{1}﹩, ﹩\mathrm{A}\,^{\prime }_{2}﹩ (thick and thin solid lines), and ﹩\mathrm{B}\,^{\prime }_{1}﹩, ﹩\mathrm{B}\,^{\prime }_{2}﹩ (dash‐dotted and dotted lines). Top panels: Time variations of centroid shift (Δλ) and width (δλ) of the Ca XIX w line profiles. The vertical dotted lines mark times when the heat input starts in individual loops, and the vertical dashed (case ﹩\mathrm{A}\,^{\prime }_{1}﹩, ﹩\mathrm{A}\,^{\prime }_{2}) ﹩ and dash‐dotted lines (case ﹩\mathrm{B}\,^{\prime }_{1}﹩, ﹩\mathrm{B}\,^{\prime }_{2}) ﹩ represent when the final heat input terminates. Bottom panels: Δλ‐δλ diagrams for loop orientation θ = 0°. The arrows indicate the direction of time evolution.