Beginning with the letter 'I' at the top of the pyramid, descend one word at a time to reach a 12-letter word at the bottom. Each word in the pyramid contains all the letters of the word directly above it, plus one extra letter revealed on the right.
Great idea! Not that it changes much, but you could have put a definition for 'I', too. I thought of this because I realized that when trying to find an answer you can try anagramming the letters in the 'add' column up to the definition you're reading but you also have to remember to add 'I'. (hope that was clear!)