Window frost (also called fern frost or ice flowers) forms when a glass pane is exposed to very cold air on the outside and moderately moist air on the inside. If the pane is not a good insulator (such as a single pane window), water vapour condenses on the glass forming patterns. The glass surface influences the shape of crystals, so imperfections, scratches, or dust can modify the way ice nucleates. If the indoor air is very humid, rather than moderately so, water will first condense in small droplets and then freeze into clear ice.
Photo credit: Bill Storey
chemistry is the actual worst
Colwyn Thomas (South African) - Roots, Commissioned piece for Iron Fist clothing Drawings