The 40 Inventive Principles are the clever ways the world has found (so far) to solve contradictions. For example, one kind of contradiction is that you want something big and small – you might want something small at one time, but then big at another time, such as a ship in a bottle which has to be small to get into the bottle but then big when it is inside. This is typically done using Inventive Principle No.15, Dynamism (the boat folds down small to get through the narrow bottle neck, and then can be unfolded when it is inside the bottle).

Another example is an umbrella, which you want big when it is raining and small at all other times. Contradictions have always existed, and people have always found clever solutions to them. However, what TRIZ has done has catalogued all the ways of solving contradictions and distilled them down into a list of simple but clever concepts – the 40 Inventive Principles! If you want to read more about contradictions and the 40 Inventive Principles, check out Chapter 3.

Each of the 40 Inventive Principles has a number of flavours or suggestions; for example, Inventive Principle No. 1 suggests three ways your system can be segmented. This appendix includes all the Inventive Principles with technical, management and general examples of these principles put into practice.

Inventive Principle 1: Segmentation

• Divide an object into independent parts
  • Flat-pack furniture
  • Segmented tent poles
  • Sales teams have different markets/geographical areas
• Make an object easy to take apart
  • Quick-release bicycle wheels
  • Use contract workers instead of permanent employees
• Make the object even more fragmented or segmented
  • Many small, local offices rather than one large HQ
  • Telecommute: employees work from home

Inventive Principle 2: Taking Out

• Take out a problem
  • Air conditioning in the room, noise elsewhere
  • Light pipes: get light where needed without heat
• Only get what you need
  • Scarecrow
  • Buy-in expertise
  • No-frills hotel

Inventive Principle 3: Local Quality

• Change an object from uniform to non-uniform
  • Ergonomic knife handles
  • Offer different products or use different marketing strategies for different geographical markets
• Change the environment from uniform to non-uniform.
  • Working hours phased to accommodate people working on international, shifted time-zone projects
• Make each part of an object function in conditions most suitable for its operation
  • Night-time adjustment on rear-view mirror
• Make each part of an object fulfil a different and useful function
  • Hammer with nail-puller

Inventive Principle 4: Asymmetry

• Change the shape of an object from symmetrical to asymmetrical
  • Funnel with off-set exit for faster flow rate
  • Use a different marketing approach for different types of clients
• Change the shape of an object to suit external asymmetries
  • Ergonomic running shoes
• If an object is asymmetrical, make it more asymmetrical
  • Different running shoes to suit users’ running styles

Inventive Principle 5: Merging

• Join objects or operations together
  • Bi-focal lenses
  • Crew members in McDonalds
• Join parallel operations in time
  • Include your customers and suppliers in design phase
  • Work on a project in parallel rather than in series

Inventive Principle 6: Multi-Function

• Make an object perform multiple functions; eliminate the need for other objects.
  • Swiss Army Knife
  • ‘One-stop shopping’ – supermarkets sell insurance, banking services, fuel, newspapers and so on.

Inventive Principle 7: Nested Doll

• One object is placed inside another; which, in turn, is inside another, and so on.
  • Shopping centres/malls
  • Nested tables
  • Measuring cups or spoons
• One object passes through another
  • Telescopic car aerial
  • Tape measure

Inventive Principle 8: Counterweight

• Compensate for the weight of an object by joining it with another object which provides lift.
  • Hot-air balloons
  • Kayaks with integrated foam floats
  • Build teams of different personality types
• Compensate for the weight of an object by making it interact with the environment
  • Maglev trains use magnetic levitation to create lift and propulsion, reducing friction and allowing for higher speeds
  • Use renewable energy to reduce a company’s carbon footprint
  • Boost popularity by connecting with popular causes; for example, charities

Inventive Principle 9: Prior Counteraction

• Add a counteraction to manage a downside
  • Make clay pigeons out of ice or clay
  • Off-set carbon emissions
  • Give generous severance packages when making redundancies
• Create beforehand stresses in an object that will oppose known undesirable working stresses later on
  • Pre-stressed concrete compensates for concrete’s weakness in tension
  • Ergonomically assess workstations

Inventive Principle 10: Prior Action

• Do a required action in advance
  • Practise emergency procedures in advance of crisis
  • Agree meeting agendas in advance
  • Arrange objects conveniently so they can go into action without loss of time
  • Just-In-Time production
  • In-store bakeries

Inventive Principle 11: Cushion in Advance

• Prepare emergency means beforehand to compensate for the relatively low reliability of an object
  • Back up computer data
  • Contingency planning
  • Have more than one person trained in skills critical to the company

Inventive Principle 12: Equal Potential

• Change the conditions of work so that an object doesn’t need to be raised or lowered
  • Mechanic’s pit in garage (car isn’t lifted)
  • Grow the job rather than promote the person

Inventive Principle 13: The Other Way Round

• Do the opposite action
  • Cash-back in stores: customers take money away instead of security firms
• Make movable parts fixed, and fixed parts movable
  • Home-shopping
  • Treadmills
  • Wind tunnels
• Turn the object upside down
  • Customers create their own product, for example, radio listeners dialling in for talk shows or to give traffic updates
  • Tomato sauce bottle with opening on the bottom

Inventive Principle 14: Spheres and Curves

• Switch from flat surfaces to spherical ones; from parts shaped as cubes or rectangles to ball-shaped structures
  • Mezzaluna (knife shaped as a half-moon)
  • Arches and domes for strength in architecture
  • 360-degree appraisals
• Use rollers, balls, spirals, domes
  • Rotary pizza cutter
  • Ballpoint pens
  • Archimedes screw
  • Make repeat purchases easy (such as direct debits, subscriptions)
• Go from linear to rotary motion, use centrifugal forces
  • Push–pull to rotary switches (for example, lighting dimmer switches)
  • Loyalty schemes

Inventive Principle 15: Dynamism

• Change the object or environment to work the best at every stage of work
  • Adjustable steering wheel (or seat, back support, mirror position and so on)
  • Different price and positioning for products throughout their life
• Divide an object into parts that can move relative to each other
  • Bifurcated bicycle saddles
  • Folding chairs
• If an object is rigid, make it movable
  • Bendy drinking straw
  • Hot-desking
  • Virtual 360-degree tours online

Inventive Principle 16: Partial or Excessive Action

• If it’s difficult to get 100 per cent of an action, go for more or less
  • Overfill bottles on production line
  • Overspray when painting, then remove the excess
  • Ensure happy customers by providing exceptional customer service
  • Show products and services online even if it’s not possible to purchase online

Inventive Principle 17: Another Dimension

• Move to another dimension: from one to two or three dimensions
  • Coiled telephone wire/garden hose
• Go from a single layer to multi-layers
  • Multi-storey car park
  • Hierarchy of command
• Tilt an object or turn it on its side
  • Cars on road transporter inclined to save space
• Use the other side of an object
  • Print on both sides of paper
  • Electronic components mounted on both sides of circuit board

Inventive Principle 18: Mechanical Vibration

• Make an object vibrate
  • Electric toothbrushes
• Increase the frequency of vibration (up to ultrasonic)
  • Sonic toothbrushes
  • Sonic facial brushes
• Use an object's resonant frequency
  • Break up kidney stones with ultrasound
  • Tuning fork
  • Use piezoelectric vibrators instead of mechanical ones
  • Quartz watches
• Use combined ultrasonic and electromagnetic field oscillations together
  • Ultrasonic and electromagnetic pest repellers deter both mice and insects

Inventive Principle 19: Periodic Action

• Go from continuous action to periodic or pulsating actions
  • ABS brakes
  • Flashing bicycle lights
  • Change leadership: many university heads of department only lead for a year, senior academics rotate leadership
• If an action is already periodic, change the rate or level of change
  • Appraise performance more regularly than annual reviews
• Use pauses between actions to perform a different action
  • Perform maintenance work during slow periods
  • Inkjet printer cleans head between passes

Inventive Principle 20: Continuous Useful Action

• Carry out work without a break
  • 24-hour manufacturing
  • Hospital emergency departments
• Remove idle or intermittent actions
  • Kayaks use double-ended paddle to utilise recovery stroke
  • Multi-skill workforce to enable them to perform other tasks when their core job has quiet periods

Inventive Principle 21: Rushing Through

• Do a process, or certain stages (which are harmful or dangerous) at high speed
  • Cut plastic faster than heat can propagate in the material, to avoid deforming the shape
  • Immediate dismissal

Inventive Principle 22: Blessing in Disguise

• Use harmful factors (particularly, harmful effects of the environment) to get something good
  • Pain can be useful feedback to stop doing something; for example, walk on broken ankle
• Remove a harmful action by adding another harmful action
  • Reduce traffic in cities by introducing a congestion charge
• Increase a harmful factor so much that it is no longer harmful
  • Restrict supply of goods to create scarcity value (such as designer handbags)

Inventive Principle 23: Feedback

• Introduce feedback
  • Customer surveys
  • Feedback forms after training
  • Exercise apps that inform you of distance run, average speed, calories burned
• If feedback is already used, make it more effective
  • Go from paper feedback forms to interviews or online surveys
  • Share information from exercise apps on social media

Inventive Principle 24: Intermediary

• Use an intermediary object to pass on an action
  • Play guitar with a plectrum
  • Marriage counsellor
  • Travel agent
• Temporarily join an object with another (easily removable)
  • Oven gloves for hot dishes
  • Bridging loans
  • ‘The A-Team’

Inventive Principle 25: Self-service

• An object services, maintains and repairs itself
  • Self-cleaning ovens
  • Wikipedia
  • Customer loyalty reward schemes (such as Nectar cards) collect information about individual’s purchasing decisions to target services and products
  • Bicycle tyres filled with gel to seal punctures instantly
• Use waste (or lost) resources, energy or substances.
  • Use heat from a process to generate electricity (co-generation)
  • Use travel time to work

Inventive Principle 26: Copying

• Replace unavailable, expensive, complicated, fragile objects with cheap, simple copies
  • Scan rare, historic books and documents, so they are accessible to all and the original remains protected
• Replace an object, or process with optical copies
  • Measure an object from a photograph
  • Product manuals as PDFs rather than printed booklets
  • Online training instead of classroom training
• If visible optical copies are used, move to infrared or ultraviolet; use unusual ways of seeing/viewing situations
  • Police helicopters use infrared to track suspects
  • Evaluate customer satisfaction in multiple ways, for example, interviews, questionnaires, observing customers use product

Inventive Principle 27: Cheap, Short-Living Objects

• Replace an expensive object with many inexpensive objects that don’t last as long
  • Disposable serviettes, napkins, cups, cameras
  • Automate work procedures and have low-skilled, low-paid staff who are easily replaceable
  • Make product cheap and easily replaceable instead of reusable, for example, contact lenses, nappies, low-cost clothes

Inventive Principle 28: Replace Mechanical System

• Replace a mechanical system with a sensory one (optical, acoustic, taste or smell)
  • Lights and bells rather than secure barriers at rail crossings
  • Smell of baking bread to entice shoppers
  • Security systems
• Use electric, magnetic and electromagnetic fields to interact with the object; use influence instead of rules
  • Magnetic bearings
  • TV remote control
  • Use staff loyalty to encourage good behaviour
• Replace stationary fields with moving unstructured fields; replace unstructured fields with structured ones
  • Hot desking
  • GPS sensors inform central control point of location of delivery vans, taxis
• Use fields in conjunction with field-activated (such as ferromagnetic) particles
  • Ultrasonic welding

Inventive Principle 29: Pneumatics and Hydraulics

• Use gas and liquid parts of an object instead of solid parts (for example, inflatable, filled with liquids, air cushion, hydrostatic, hydro-reactive); use flexible influences instead of solid rules
  • Inflatable mattresses
  • Hovercraft
  • Use guidelines, not rules
  • Create a ‘health and safety culture’ instead of a long list of rules

Inventive Principle 30: Flexible Membranes and Thin Films

• Use flexible shells and thin films instead of three-dimensional structures
  • Tarpaulin car cover instead of garage
  • Open-plan offices
• Isolate the object from the external environment using flexible shells and thin films
  • Bubble-wrap
  • Bandages and plasters
  • Offices with cubicles

Inventive Principle 31: Porous Materials

• Make an object porous or add porous elements (inserts, coatings and so on)
  • Cavity wall insulation
  • Foam metals
  • ‘Open door’ management policies
• If an object is already porous, use the pores to introduce a useful substance or function
  • Medicated dressings
  • Train customer service teams to sell additional products and services (for example, at shop tills)

Inventive Principle 32: Colour Change

• Change the colour of an object or its surroundings
  • Colour-changing paint or sun cream
  • Light-sensitive glasses
• Change the transparency of an object or its surroundings
  • Make organisation’s objectives and decision-making processes clear to everyone
  • Transparent solar cells (make every window/screen a photovoltaic solar cell)
• Observe objects or processes that are hard to see by using coloured additives
  • Use opposing colours to increase visibility (for example, butchers use green decoration to make meat look redder)
• If additives are already used, monitor things that are hard to see by adding luminescence/other markers
  • UV marker pens to identify stolen goods (only seen under ultraviolet light)
  • Get potential customers to register interest with special offers

Inventive Principle 33: Uniform Material

• Objects interacting with the main object should be made of the same material (or one with similar properties)
  • Ice cubes made of drink they are cooling (such as lemonade)
  • Wood dowel joints for joining wooden components
  • Make sure all your employees can understand and sell your products
  • ‘Mirror’ someone’s body language to facilitate easy communication

Inventive Principle 34: Discarding and Recovering

• Make objects (or part of them) that have fulfilled their useful functions go away (discard by dissolving, evaporating and so on) or modify them directly during operation
  • Dissolving capsules for vitamins and medicine
  • Bio-degradable containers and bags
  • Take on temporary staff to manage busy periods, such as in shops over Christmas
• Restore consumable parts of an object during operation
  • Sell on to ‘used up’ customer: for example, transfer student bank accounts to graduate bank accounts when they finish their course; dentists refer patients to dental hygienists
  • Self-sharpening blades
  • Mechanical pencil

Inventive Principle 35: Parameter Change

• Change the physical state (for example, to a gas, liquid or solid)
  • Transport gases as liquids
  • Liquid soap instead of soap bar
  • Deodorant as a liquid, solid stick or aerosol spray
  • Virtual organisations
  • Customer service offered remotely (by phone or chat box online) instead of face to face
• Change the concentration or density
  • Change number of staff
  • Fire briquettes: low density for lighting fires, high density for burning all night
  • Move from local to centralised distribution (or vice versa)
• Change the degree of flexibility
  • Vulcanised rubber is less flexible and stronger
  • Hot-desking
  • Flexi-time
• Change the temperature or volume
  • ‘Fire up’ and motivate employees
  • Increase individual’s scope of responsibility
  • Heated butter knives and ice cream scoops
  • Butter knives with built-in grater to soften cold butter
• Change the pressure
  • Pressure cooking is faster
  • Manipulate stress levels (increase near deadlines)
• Change other parameters
  • Semco: staff set their own wages, production targets, working hours
  • Thixotropic paints are viscous so they don’t drip, but become runny when shear force is applied by the brush against the surface being painted.

Inventive Principle 36: Phase Changes

• Use phenomena occurring during phase changes (volume changes, loss of absorption of heat and so on)
  • Latent heat effects in melting or boiling
  • Break rocks by soaking in water and then freezing
  • Individuals try harder when proving themselves; for example, graduates, new to the post, newly promoted: use these people for difficult projects/those requiring long hours

Inventive Principle 37: Thermal Expansion

• Use expansion (or contraction) of materials by heat; responsiveness to circumstances
  • Be very responsive to change; for example, have extra staff available for busy periods
  • Emergency services available to deal with crises
  • Shape memory materials
  • Shrink-wrapping
• Use multiple materials with different coefficients of thermal expansion; use multiple and different systems that respond to circumstances differently
  • Bi-metallic strips used in thermostats
  • Different emergency services offer different expertise in major car crashes, for example, police create safe space on road and prevent other crashes; fire service to cut people out of cars; ambulance knows how to move injured people.

Inventive Principle 38: Boosted Interactions

• Enrich the atmosphere
  • Create a competitive atmosphere to motivate sales team
  • Oxygen tent for asthmatic patients
  • Nitrous oxide injection for power boost in engines
  • Create the right atmosphere for different working environments: places with buzz for team working and discussing ideas; quiet zones for independent working
• Create a highly enriched atmosphere
  • Use highly charismatic leaders to engage the workforce
  • Irradiation of food to extend shelf life
• Enrich the atmosphere with unstable elements
  • Staff charged with energy through uncertainty: such as fear (threat of redundancy) or rewards (bonuses/promotion)
  • Use ozone to destroy micro-organisms

Inventive Principle 39: Inert Atmosphere

• Replace a normal environment with an inert one
  • Libraries’ quiet environment creates a good environment to work, read and study
  • Corporate away days
  • Foam to separate a fire from oxygen
• Add neutral parts or inert additives to an object
  • Use contractors and external consultants
  • Fire retardant additives

Inventive Principle 40: Composite Structures

• Change from uniform to layered/composite (multiple) structures
  • Teams with diverse team members bring different skills and perspectives
  • Use different delivery methods in training (lectures, exercises, follow-up reading)
  • Fibre-reinforced composite materials in Boeing 787 wing and fuselage
  • Concrete aggregate