Not wanting to miss out on finishing our synonym review with an activity like this I put my thinking hat on and came up with a solution to my problem.
First step - Shading Art (& math & geometry if you are feeling desperate) - measure your paper and divide into 24 equal rectangles. Paint your boxes gradually shading to a lighter colour.
Second - when dry fill in the top box with a word and write the synonyms under.
Simple and didn't involve a trip to the DIY store ; )