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Helping Designers Understand Code

My graduate research thesis focused on devising multidimensional visualizations of programming constructs to help designers and visual thinkers understand programming concepts.


August, 2015 - April, 2016
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Introduction

My graduate research work focused on designing interactive visualizations of programming constructs to help designers and visual thinkers understand programming concepts. My tool acts as a supplement to an introductory programming course for designers, and helps designers understand code by way of observation and interaction with these visualizations. This research is valuable because programming and computational thinking are very important skills for designers to have, but syntax based instruction of these skills has been proven to not be an effective way for designers to learn.

Not only does a visual way of representing programs make it easier to learn for visual thinkers, but visual thinking can be an extremely powerful way of thinking about computations. I strove to expose the state of a program over time, which can be very helpful for a programmer of any level understand what is happening in a program at any step of the program. I used several research methodologies and based my direction on learning theories to progress through the projec.

The visual nature of programming

Many of the core concepts in modern programming can be expressed visually, and have immediately accessible visual analogues. When a knowledgeable programmer imagines implementing a loop or an event, they can draw upon a mental visual representation. When they describe these concepts, they move their hands, they gesture, they draw. Even so, to professional programmers, many of these visual programming tools seem to be a limited shortcut, that are not capable of the full range of expression that textual programming provides and are seen only as intermediary tools on the way to learning how to “actually program”. This way of thinking can hold back new and powerful ways of thinking computationally. Visual programming is inherently attractive to people who think visually, but it should be attractive to anyone who programs and can “see”.

One of the major successes of Visual Programming Languages (VPLs) is the transformation of writing code into the act of play. The very quick iteration time and the ability to quickly debug various states of the program visually, almost immediately, is a strong opportunity that can be pushed further. This plays well with designers learning through discovery.

However, existing VPLs and programming tools don’t build transferable skills in the user. Since VPLs are primarily programming languages, the main focus is on making it easy for a user to write source code rather than learn computational thinking or programming concepts. For a tool that is being used in such a developmental stage of a user’s learning journey, it is very important for the user to learn the concepts, understand the nature and working of programming constructs as well. This is a transferrable skill that can be applied to any programming language in many paradigms. In the absence of such development, if the user wants or needs to use another programming language for a project, they might run into a wall and not know how to approach resolving a bug in the code or solve a problem.

An issue specific to data flow languages is the absence of time in the visualization of transient programming constructs. In many programming environments the state of an object throughout the computation changes, but this might not be reflected in the visual feedback to the user. Exposing state over time is a powerful way to teach many computational mental models and illustrate what a computation is actually doing, as opposed to just what its output is.

In this thesis, I explore how interactive three-dimensional transient visualizations of programming constructs may help in understanding the concepts behind programming in order to implement them in various programming paradigms and languages.

Framework and context

I propose that the process of writing a program involves four stages; computational thinking, programming, coding, and computation. I base this proposition on my experience serving as the teaching assistant for an introductory programming course for designers taught by Dr. Derek Ham.



The process of writing a program: The first stage in the process involves computational thinking, which is very alike design thinking. The second stage is programming, where the computational model is rethought to fit a programming paradigm. The third stage is coding this program in a certain programming language, and the last stage is the computation itself which happens behind the scenes in the computer.


My tool and the system of visualizations is designed for the context of an introductory programming course. In the classroom, the teacher introduces the students to different topics in programming, which the student can explore via my tool. Using my designed tool to explore various programming constructs, the student would go through the various phases in Kolb's experiential learning cycle, which I base my studies on.


Here, I show the four stages of programming against Kolb's experiential learning cycle, and further relate them to interactions that a user would go through while using my tool in a classroom context.

I postulate that a visuo spatial approach to explaining the programming constructs is appropriate for design students based on Gardner's theory of multiple intelligences. My experience with design students tasked with learning programming affirms this decision.


Visual studies

An outcome of my investigations was the visualization of different programming constructs. I divide my process based on these visualizations, and talk about them in the following sections.

I use the freedom afforded by the digital visual medium to show the transient nature of various programming constructs. The visualizations are studies on different programming constructs, and are explorations into how they may be visualized such that they may be combined to form a bigger whole.

Variables

In programming, variables can have different data types, and can be either primitive or composite. I was more interested in visualizing the primitive data types. The primitive data types can be broadly classified into numerical, boolean, or character data types. These visualizations tackle the numerical variables more than the others, in part because of their broader application, and in part because of their more abstract nature.

I also look at ways to visualize things to introduce the concept of frame rates and computing power, and the relation between the two.

Two ways of visualizing a numerical variable controlled by a sin() function. The first uses a more visual approach than the second, which is more akin to plotting a mathematical function on a graph.
Comparing two ways of visualizing the variable above. The first way is not appropriate to show negative values, since the value expansion happens symmetrically about the axis. To show negative vs positive values for this approach, color coding may be used. In this the yellow represents a positive value, while magenta represents a negative value.
The second method works better in this regard since the value of a variable, positive or negative, may be judged from just the silhouette. Also see my VR Function Generator.
This visualization shows how calling a function that defines a variable at different rates can change how the function returns values. The accuracy with which the computer can recreate the programmer's function depends on the frequency with which it is called. However this visualization also demonstrates that a higher accuracy is usually accompanied with slower processing times, by giving control of each function call to the user.

Infinite loop

Targeting visual thinkers and designers, I assumed a programming language which implemented an update function which is a recurring function, and can be thought of as an infinitely running loop. Tying this with the state of the program and the elements within, I introduce the idea of function calls changing the state of variables. This also situates the more abstract concept of a variable within a programming construct.

Exposing state over time is a powerful way to teach many computational mental models and illustrate what a computation is actually doing, as opposed to just what its output is.

An interactive visualization showing an initialization function, setup(), and a recurring update() function. update() is run like an infinite loop, and this visualization was to help one visualize that the state of a function changes each time it is called. Each of the rectangles in the visualization depicts the state of the function, which never changes for setup() but is continually changing for update().
The lines and arrows show the control flow.
Here, the student has full control over the visualization, be it state changes or spatial orientation.
Continuing the discussion on states, this interactive visualization shows the value of a variable changing only each time the function is called.

Conditional loop - for()

The for() loop can be seen as a combination of an infinite loop and a conditional statement. The for() loop is designed to run for a limited number of times, as long as a certain condition is met.

With this visualization, I introduce the code being visualized at the top for the student to see and manipulate. Manipulation of the code results in the structure of the visualized code changing. This adds a kinesthetic learning to the visual-spatial learning attribute.

The benefits of three dimensional visualizations for programming constructs is made more clear with a more complex construct like this one, as I show here.

The for loop going through its iterations, each iteration being called by the user to see the values of each variable change within the construct definition.
The user can hover over a line of code to see what it corresponds to in the visualization. This forms a connection between the visual representation and the code syntax, and helps the visual thinker retain that connection for the concept.
The user can also change the value of the selected element, from the counter variable to the limit for the for loop, as well as the variables defined within the construct. Changing any variable also changes all other dependent variables.
The user can change the orientation of the 3-Dimensional visualization. The three dimensionality adds to the user's understanding of the construct and how it affects other elements of a program. Here, the top view shows the user that the values of some variables change a lot with increasing iterations, while some stay very close to initialization. Another view shows the user how one variable is linked to the others - one variable serves as the trend line, while others change the values respective to the trend.

The tool interface

I designed a tool that a student can use in the classroom context to explore various visualizations of programming constructs to help her understand the working behind them. I also prototyped it in Processing, and the low fidelity prototype is shown here.

The tool makes all the programming constructs being covered in class accessible to the student, as well as displaying several examples covering various topics. Details of interactions are shown in the screen captures.

Step 1: Selecting a construct to explore, guided by what is being taught in the classroom and / or what the student wants to learn.
Step 2: Exploring the three dimensional visualization of the construct. The student has control over the state of the construct, be it a variable, function, or constructs like loops and conditionals.
Step 3: The student can switch to another construct once she thinks she has understood the principles behind the first, selecting from the list of constructs on the left.
Step 4: If she so wishes, the student may select an example that demonstrates the construct in question from the example list on the right. The interface changes visually to show that the nature of the investigation has changed, and the student may alter the code behind the visualization now.
Step 5: With a better idea of how the constructs may be used, the student returns to the main menu to get an overview between the relationships between different constructs and how they may be used together by looking at the list of examples on the right.