The yellow blocks are straw blocks, don't really know the correct english term for it^^
They should block the way of the farmer. In fact they are the best way to do so. There is an imba tactic with using them against the other player.
It seems like you played the game alone. The usage of the items gets more clear if one plays the farmer and one tries to place the items to defend the chickens.
And yeah you may be right with the swear thing because of young folks participating here. Normally I just code for me and my mates, so swearing wasn't a problem till now.