My early concepts consisted of quick 3D models in rhino (as shown below)
On the left example, I was trying to achieve a premium aesthetic to the pump. The glass center would have the user see the gas as it goes through the tube and into their car, however this seemed hazardous.
On the right example, I continued with the tube idea although this time the tube would light up with the same color as the type of gas chosen (Red=Premium). This was the better example out of the two and what my final design is based off of.