Top: examples of 200 (left), 300 (middle), and 400 (right) 2D Gaussian structures injected on top of an fBm image with β = 2.4. The Gaussian structures are randomly sampled using the distribution functions of the major axis size and aspect ratio distributions of the Hi-GAL clumps. The column density contrasts are randomly sampled from a distribution with ψ = 2.5. All syntheticmaps are convolved with a beam whose FWHM = 18.2′′. Bottom: Δ-variance spectrum of the synthetic models for cases with N_s = 200 (left), N_s = 300 (middle), and N_s = 400 (right) injected structures. Each synthetic spectrum is the average over 25 realizations, and the full lines represent the 1σ dispersion around the mean. The synthetic Δ-variance spectra are compared to those of the Cygnus-X North region and an fBm with β = 2.4.