As per the rules of the contest, in order to join the game, you have to propose a photo in the comment section of my post. The photo must contain the two subjects indicated in the post (this week they are wood and book). With your photo, you must add a third subject of your choice (as for the other two, the photo must also contain the subject you chose).
For example, a valid subject for your entry could be: Cat.

Let me know if you agree with "cat" or you want to propose another subject.

If you want to join again, read the rules section of my post. There are also some other rules to follow in the choice (you mustn't use proper names or add more words as a subject).