V_ϕ of the overdensities at V_R = −60 km s⁻¹ for an entire turn around the model of the galaxy. Left: Results for the SBM. Right: Results for the FBM. Top: Structures for t₂ = 4 bar laps. We observe how the arches seen in the fiducial models are part of the same global structure, linked through a 180 deg symmetry (dashed red lines). Middle: Structures for t₂ = 10 bar laps. The resonant regions start to be clear, and the structures in the middle are flatter and closer between them. Bottom: Structures for t₂ = 40 bar laps. The resonant regions are clearly defined, and the middle region is crowded with flat structures. The vertical dashed lines mark the location of the Sun.