Question: Which models are lighter than 3500 but not built by the 'Ford Motor Company'?
SQL: SELECT DISTINCT T1.model FROM MODEL_LIST AS T1 JOIN CAR_NAMES AS T2 ON T1.Model  =  T2.Model JOIN CARS_DATA AS T3 ON T2.MakeId  =  T3.Id JOIN CAR_MAKERS AS T4 ON T1.Maker  =  T4.Id WHERE T3.weight  <  3500 AND T4.FullName != 'Ford Motor Company';