Is this an angry piece of wood? No it isn't — it's a word game. An acrostic is a puzzle in which the first letters of each line spell out a word. So if you arrange these terms of enthusiasm one above the other, you will produce another word which is far from enthusiastic:
You can spell out people's names in this way. Or you can pass secret messages to each other.
You can even go a step further and have an acrostics competition. One player thinks of a word (a town, for example). Then he gives a clue for each letter of that word. If the town were London, the clues might go like this: 'The middle of a pencil: (Lead), 'A bird that hunts at night' (Owl), The opposite of South' (North), 'A flying elephant' (Dumbo), 'A play in which there is singing' (Opera) and 'Fivepence minus fivepence equals what?' (Nought). The clues can be made easy or difficult depending on who is playing the game.