Supplementary video of the article Ardèvol et al. 2025, "Spiral arms across stellar populations in simulations via the local dimension method" (http://arxiv.org/abs/2507.15473).The video shows the temporal evolution of local dimension, D, maps in log-polar coordinates between simulated times 12.5 and 13 Gyr for all stellar particles (top), those younger than 0.5 Gyr (middle) and those older than 10 Gyr (bottom).Contact: jardevol@icc.ub.edu Funding: This work was part of the PRE2021-100596 grant funded by Spanish MCIN/AEI/10.13039/501100011033 and by ESF+. It was (partially) supported by the Spanish MICIU/AEI/10.13039/501100011033 and by "ERDF A way of making Europe" by the “European Union” and the European Union «Next Generation EU»/PRTR, through grants PID2021-125451NA-I00, CNS2022-135232 and PID2024-160244NB-100, and RED2022-134612-T; and the Institute of Cosmos Sciences University of Barcelona (ICCUB, Unidad de Excelencia 'María de Maeztu') through grant CEX2024-001451-M and the project 2021-SGR-00679 GRC de l'Agència de Gestió d'Ajuts Universitaris i de Recerca (Generalitat de Catalunya). ARP acknowledges the support of the National Science Foundation grant Launching Early-Career Academic Pathways in the Mathematical and Physical Sciences: award 2418980. The simulation was run at the DiRAC Shared Memory Processing system at the University of Cambridge, operated by the COSMOS Project at the Department of Applied Mathematics and Theoretical Physics on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk). This equipment was funded by BIS National E-infrastructure capital grant ST/J005673/1, STFC capital grant ST/H008586/1 and STFC DiRAC Operations grant vST/K00333X/1. DiRAC is part of the National E-Infrastructure.