Finding a clear space in the games room I filled three sandwich bags with paint. One for each primary colour. Then I placed a small piece of white paper behind each one and using electrical tape I taped each one to the floor. The paper behind the bags allows the spaces created to show up in the paint much easier.
Cakes used her hand to smudge it, her finger, paddlepop sticks and cotton tips to make marks. We made squiggles, straight lines, shapes, letters, numbers and drew a few pictures also. This has now been set up on the floor for 6 months and is still used on a weekly basis. The only issues that have arisen is a small hole pierced in the yellow bag from overuse (nothing a little bit of sticky tape cannot fix).