SEATTLE — Building a better bank? Do it in the sandbox.

Financial innovator Kosta Peric’s concept of the castle and the sandbox, which is also the title of a book he wrote, means that while banks need to be protective and close themselves off from the world, and for good reasons, they should also maintain sandboxes — places where innovation and experimentation can happen. Peric, formerly director of Innotribe and now deputy director of financial services for the poor at the Bill & Melinda Gates Foundation, spoke about the need for sandboxes with Bank Innovation editor JJ Hornblass at Bank Innovation 2014 in Seattle earlier today, and Peric’s messsage was a loud one: banks today need both castles and sandboxes, but unfortunately many lack the latter.

This theme was echoed by Michael Dooijes, Rabobank’s executive director, head of strategy & innovation, who said that a digital bank should be built “in parallel” to an existing bank, “not on top of it.” This way, the digital bank is not a reflection or reproduction of an existing set of processes, but an entirely new one.

Dooijes both works at a bank and is the CEO of a startup, mobile ordering service MyOrder. A majority stake in MyOrder is owned by Rabobank, but the company largely operates independently, according to Dooijes. MyOrder has 200,000 customers, and Dooijes wants 500,000 by yearend. Rabobank is also looking to acquire “20 to 30” startups per year, a target that startled some attendees here.

American banks may not have the same flexibility and freedom as Rabobank in working with startups, but there is a lot at stake. Dooijes said that 32% of bank revenue is at stake due to disruptive companies and technologies. Whether or not you agree with that number, it’s time to get to work in that sandbox.

Follow today’s developments at Bank Innovation 2014 on Twitter at #BI14.