Use ultra-washable paint (1 part washable kids’ paint, 1 part dish soap) — or, even easier, chalk — to decorate outdoor toys.
A car like this one, a scooter/bike, a backyard slide…you name it, you can probably color on it. If you can’t get the chalk to stay, you can dip the chalk in water for better results.
Every time I introduce this to a kid, they’re shocked for awhile at the concept of coloring on a toy??!!!!??! You mean that’s allowed…even encouraged??
Writing, drawing, or painting on surfaces other than just a waist-height-when-seated piece of paper are so good for kids’ wrist/hand and grasp development!
And then, as a bonus extra activity, give them the hose (or some sponges) and let them play “car wash” or otherwise spray it down — that’ll buy you another 10 minutes of enthusiasm at least!