We drew a picture of a house using wax crayons.  We had to make sure that we had properly covered the paper with wax.  After that, we covered the whole piece of paper with watercolour paint.  We were a bit worried about painting over our designs but it was okay.  The paper absorbed the watercolour paint but the wax made a waterproof layer and so the paint was not absorbed over this part of the paper.  If you look closely at the picture above then you can see some drops of water just staying on the surface of the picture.