### Instruction: Classify the following as a 'triangle' or 'not a triangle' - equilateral, isosceles, right angled, circle, sphere, scalene, rectangle, square, trapezium.
### Response: 'triangle', 'triangle', 'triangle', 'not a triangle', 'not a triangle', 'triangle', 'not a triangle', 'not a triangle', 'not a triangle'.