The best source of inspiration is a closed door!

The famous Playboy centrefolds featuring the "girl next door" were actually born out of desperation. The magazine's editors couldn't find a suitable photo of a professional model from the agencies for an upcoming issue.

So they took a bold step. They photographed a half-dressed staff member and published her story alongside the photos - emphasising that she wasn't a model, just a normal woman.

To their surprise, hundreds of everyday women queued up to be featured in future issues.

From then on, Playboy had no trouble finding models for its centrefolds.

The lesson: if you feel stuck or desperate in your start-up, don't keep banging your head against a closed door. Instead, look inside and ask yourself what unexpected internal resources you could use to solve the problem.

No need to get naked - just think creatively.