The following is a computer version of an exercise first shown to me by the late R. B. Woodward, Nobel Chemist at Harvard. He had written the names of the colors in different inks on a piece of paper and asked me to tell him which color each word was written in. It was quite a challenge. Years later I decided to implement a version of this for the web. (Of course you can still do the exercise as I first did; simply go down the list and say the color of each word aloud . There just won't be any witnesses!)

As the color of the block below changes, position your mouse over the name of the color that appears. In other words, if the block turns red, then place your cursor over the word "red" in the column on the right. Do you have a little trouble landing on the right word? You're not alone.