When an unoccupied intersection is surrounded by ships of the same colour this is called an eye intersection or ‘eye’. An eye is formed from the withdrawal of a trapped ship or may be formed just from the course of play. Placing, moving, or knocking your own ship into an opposing eye is not allowed unless it results in the immediate trap of an opposing ship forcing the next play to be a withdrawal by the opponent. This kind of situation is called a 'mixed traps position'.