Or how to think in human constrains…Ever wondered how to open a locked secure-coded door when carrying lot of stuff? Here you are (Video 1:09min):

Tip-toe concept was developed by Anders-Petter Andersson, Åsa Harvard and Jonas Löwgren in 1999 and it´s part of a compendium about how to use video to represent and express interaction design.

It really deserves a visit.