This is a cookie icing machine built using the Mindstorms EV3 kit (set 31313). Building the model is pretty straight forward, but getting it to perform well might take a little adjustment.
I have written a lot of notes about getting it to work well and the icing hardware we used on my website (just follow the links to the instructions). Quality output mostly comes down to the consistency of the icing you are using, but if you actually try to build one and get it working you should definitely go read the notes.
I'm just going to keep all the operation notes over there so I don't have to update them in multiple places as I add more. I may even update the program file to improve performance over time.