2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/130890We prove formulae for the countings by orbit of square-tiled surfaces of genus two with one singularity. These formulae were conjectured by Hubert & Lelièvre. We show that these countings admit quasimodular forms as generating functions.22 pages, 6 figuresGeometric TopologyNumber TheoryMSC 2000: 32G15 05A15 11F11 11F23 30F30 14H55text