[ Thanks to kiterunner for this link.
“SwipePad is a simple application that lets you launch any app
with a single swipe action from within any other app. Upon being
recommended by a friend of mine, SwipePad was one of those
applications I installed immediately after receiving my first
Android phone. Since then, SwipePad has become an integral part of
my daily life that I almost started seeing it as one of those core
apps for Android which comes as default.”