Use arrow keys to move the cursor and press space to "click." To exit the text box press the "b" key, it may take a couple of tries since this is still a work in progress. When moving the square you can turn it using the "a" & "d" keys.
I got the idea for this after seeing some old computers online that used the arrow keys to move the cursor. Or maybe my mind just screwed up my perception, oh well. Updates: V1: Shared this project. V1.1: Added a grabbable and movable object. V1.1.1: Added a second grabbable and movable object that you can turn.