Often, finding an innovative solution is based on finding similarities between things that might not usually be considered similar.

Identify a key characteristic or function of a conventional solution. Then think of as many other designs that share that one characteristic only. Once you have thought of as many alternatives as possible, go through them and weed out the silly ones.

Some examples include:

• Ballpoint pens are either retractable or capped, but all fountain pens are capped. Therefore, design a retractable fountain pen (such as the Namiki Pilot "vanishing point" fountain pen).
• Elevators usually lift using cables hung from above. However, hoists lift things of comparable mass too, only over shorter distances. So in low buildings like shopping malls, elevators are often designed as hoists.

See also oppose convention.