Peter and Jane have a ladder that is 12m long. The shed they need to fit it into is only 8m long. Jane remebering her physics lessons knows that an object traveling at near light speeds cause the object to distort in in length in the direction of speed therefore making the ladder appear to Jane (who is stationary) short enough to go in the shed. You can work this bit out but, it will be somewhere near 8/10 the speed of light. So Peter starts running at this speed when to his horror he relises that it is relative to the frame you are in. To him it is not the ladder that has shrunk in length but, the shed. Jane being in another frame sees nothing wrong as Peter runs into the shed and slams the door. At the moment the door shuts but the ladder is still moving, where is the ladder, inside or outside the shed?
