You will need:
A canvas (you could also use thick paper)
Range of paint colours
Stick the masking tape on the canvas in random lines so that it criss-crosses itself several times, creating a range of shapes between the tape. Paint each shape a different colour. Try not to have any adjacent shapes the same colour. Once dry (I used a hairdryer) add patterns to each shape using a smaller brush. The challenge is to use a different pattern on each one! Allow to dry again and then very carefully remove the tape in the order you stuck it down.