We know that every symbols represent a present character, but there is a curious thing : In the second journal, the author drew the wheel, it was a long time before the birth of Kids/teens (Mabel, Dipper, Gideon, Wendy, etc)... So, What does it mean ? Repeated History or predictions ? I lean towards the prediction, because the author already predicted a disaster (see episode 2, season 2), we know something is going to happen in 2012... Plus, he certainly met Bill Cipher. Did he make a deal with him ? (see "Author")