40 principles of inventive problem solving

1. Segmentation
2. Extraction
3. Local quality
4. Asymmetry
5. Combining (Integration)
6. Universality
7. Nesting
8. Counterweight
9. Prior counteraction
10. Prior action
11. Cushion in advance
12. Equipotentiality
13. Inversion
14. Spheroidality
15. Dynamicity
16. Partial, overdone, or excessive action
17. Moving to a new dimension
18. Mechanical vibration
19. Periodic action
20. Continuity of useful action

21. Rushing through
22. Convert harm into benefit
23. Feedback
24. Mediator
25. Self-service
26. Copying
27. An inexpensive short-life object instead of an expensive durable one
28. Replacement of a mechanical system
29. Use a pneumatic or hydraulic construction
30. Flexible film or thin membranes
31. Use of porous material
32. Changing the color
33. Homogeneity
34. Rejecting and regenerating parts
35. Transformation of physical and chemical states of an object
36. Phase transition
37. Thermal expansion
38. Use strong oxidisers
39. Inert environment
40. Composite materials

Formulation by Karen Tate and Ellen Domb