More recently, you have settled into a fashionable office, other employees are not yet accustomed to you. You often like to stay on longer at work. On one of those days, they just locked you inside and went home. Wait until the morning you do not want this, you went to search for a spare key. The chief said that it is hidden somewhere in the middle of the room. The building has a new security system, which in turn has a type of rebus.