Make a keyboard shortcut to do three finger swipes

How do I create a keyboard combination that can be held down to treat the successive mouse moves as if they were three-finger-on-trackpad movements? So I can hold down e.g. cmd and shift, then move the mouse, and it would be as if I were performing that movement with three fingers, to perform things like - change spaces - expose mission control - show application windows There are of course already individual keyboard shortcuts for all of the three-finger trackpad actions. However, these are (often) two-handed keyboard shortcuts. I would like to configure a left-hand only "modifier", which will then treat my next mouse move as if it were performed with three fingers.