Freehand patterned rainbow I drew on my window this weekend using chalk marker pens. I love seeing window drawings on my daily walk around the block. : r/CasualUK
Window Art and Chalk Work – INGRID BARTKOWIAK
How to Draw and Write on Windows With Liquid Chalk Markers - FeltMagnet
Paint It Forward with NiNo Alicea - Chalkola - Chalkola Art Supply