Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field. 
User interfaces for interaction with machinery are well know.  From computer keyboard and display to large music panel type devices, these arrangements are in common use in society.  Various advances have also been made.  For example, a known user interface devices includes the prototype Optimus keyboard.  Each of the keys on the Optimus keyboard has a discrete display showing the function of the key at that moment.  When the function of the key changes, the display on the key changes to the new function of that key.  This helps the user to quickly adjust to controlling new programs or devices however it is relatively expensive technology limited to depressible OLED keys.