This trade-off really asks for a fast visualization method and therefore some clever designers and programmers invented Rapid Paper Prototyping. Quick and dirty interface prototypes are sketched with pen and paper to be tested (and re-designed) with all the limitations physical paper brings along.

But today, in the digital age, Rapid Paper Prototyping has grown up! The era of digital interface prototyping has begun. With digital wireframing tools you can create interface mockups by drag and drop from prefabricated stencils (elements like checkboxes, navigation bars etc.). Unlike paper, these digital interface prototypes are completely interactive with animated navigation, real type-in form fields and linking between all pages through buttons and text links.