OK, I completed this game once before but my memory not being what it was, I can not remember how I made the wooden cog, I know it's made from the old tree stump and I have the two statues in place and it tells me I need the cog, but no matter where I drop my master builder or master scientest or perfect villager at around/on it does not make the cog, so what am I forgetting? Please and thank you