I know I've pinned this here before - Moss Graffiti. Just mix some moss collected elsewhere with yoghurt or buttermix in a blender and apply with a brush to a textured/porous wall like brick or concrete. Spray with a water mister if the weather is dry.
Got some old tires on hand? Here have some garden ideas share with you. You can easy build a tire garden! Keep it simple with a small stack, or get creative using paint. Or plant some vegetables, or DIY some garden decorations….