Our final prototype takes users from the "I got the bill; how much  should I pay?" stage to the "This is how much I owe; now how much  should I pay?" stage. Usually, in a restaurant, payers have to think  about several things when coming up with the payment amount, including: 
		   - should we split the bill evenly?
		   - how much did each person get?
		   - how to account for tip/tax?
	    In  the end, however, what they really are interested in is how much they  should put on the table. What our prototype does is walk them through  this process, record what information they can easily figure out (what  percent do they want to tip, who should split what, etc) and calculate  how much they should pay if they had exact change--the subsequent  rounding and owing procedures are left up to the user.
A flow diagram for our prototype is provided below, and covers in detail what our prototype allows people to do. Because our prototype is functional enough to accurately show its attempted capability, we do not describe this in too much detail.

The full implementation of our final prototype was done in JavaScript  and PHP. Each page (a block in the flowchart) was implemented as a  seperate webpage, and communicated to other webpages using PHP POST and  GET. The menu items were hard-coded in a JavaScript header file, which  was included in all of the pages. The prototyping for this, in  software, was done in two phases: first in PowerPoint, then in  JavaScript. The advantage of using PowerPoint was that everyone in the  group was familiar with it, and could easily manage the organization  and creation of design features. The PowerPoint prototype also ended up  being a very good layout device, in providing clear indication of the  code structure needed before any JavaScript was written. 
          
          One  of the most important aspects of our interaction, however, was  drag-drop, and to implement that, we needed something more dynamic, and  so the final prototype was implemented in JavaScript. This was mainly  decided based on personal preference, resulting from previous  experience, ease of finding tutorials, and general transparency of the  language. Although the language itself didn't really afford too many  disadvantages, the extent in which it was used turned out to be a  bigger factor. The day after the first prototype was completed, it was  discovered that a free JavaScript package existed for coding for iPhone  webapps, affording several unimplemented features, such as:
           - ability to be functional on an iphone
           - standardized keyboards, buttons, and headers
          
        The  other main feature that JavaScript and PHP alone were insufficient to  preform is the bill-loading system itself. Originally, we imaged that  at many restaurants, bills, when loaded into their own financial  system, can also be accessed and viewed from the iPhone, using the  paycode found on the receipt. To simulate this, we provide the testers  with two standardized receipt, whose items are hard-coded into the  system. Overall, however, because of the little backend required in our  prototype, we were able to provide a very close simulation in design to  what we had intended to produce.
The final prototype can be found at:
All features have been implemented. However, this prototype currently only has one receipt which you can use to split the bill: