Mario Cardinal

"The real voyage of discovery consists, not in seeking new landscapes, but in having new eyes" – Marcel Proust

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Single Responsibility Principle

In this post, I explain why the value proposition of the first version of the Slingboards Lab home page was not clear.

An entrepreneur is a creator. One of the challenges that awaits every entrepreneur is to succeed creating simple things with only one responsibility. Everything an entrepreneur creates should do one thing, and no more. In software architecture, we call this rule the single responsibility principle. I learned it many years ago from Robert C. Martin. In object-oriented programming, the single responsibility principle states that every class should have a single responsibility, and that responsibility should be entirely encapsulated by the class. All its services should be narrowly aligned with that responsibility. Another way to state this principle is to say that a class should have one, and only one, reason to change.

I am reminding you of the single responsibility principle because, lately, I’ve broken this rule. It happened when I created the first version of Slingboards Lab home page.

I discovered the problem in the following days when I started testing this page with professional developers. I was mixing two very different messages. On one hand, I was trying to explain what a collaboration board is, and on the other hand, I was presenting our programming platform. Worse, I was using the word “slingboard” and the word “Collaboration boards” to express the same concept. To say the least, the value proposition was not clear. In addition, continuing my tests, I found that the primary customer segment for our product are the team leaders and not the professional developers.

Obviously, I quickly rebuilt the home page to improve our message. As expressed by my partner Erik Renaud: fail fast and learn quickly. Refactoring the website keep me busy most of my time last week. Now our Home Page has only one responsibility which is to present slingboards to team leaders. I transferred all the content that is intended for developers in the Developers Page.


What is a slingboard (part 2)

(Go to Part 1) Slingboards Lab mission is to bring your team at your fingertips. Through the provision of slingboards, it brings sticky notes to smartphones, tablets and the web for empowering teams to better collaborate.

A slingboard ensures teammates are always in sync. It provides real time feedback to everyone involved in the whole process. It highlights the flow of work and what is being done.

A slingboard allows instant access to the workflow. Remote and teleworkers can easily collaborate with their colleagues in teal time.

Here is a video that explains what is a slingboard

Because the tablet layout have the appearance of the original yellow stickies, learning to use a slingboard is simple. The familiar sticky notes essentially became the user interface. Team members can quickly embraced this new technology.

A slingboard increases accountability and positively influence the behavior and attitude of team members . Teammates define and choose their own work instead of having work assigned to them. High visibility and clear guidelines ensure teammates cannot hide work (or non-work) from each other. They know that at any moment, if they want to, they can, with zero overhead and without causing any discomfort to anyone, see exactly what everybody is doing. Boards tend to expose the flow, but it is done with ground rules that people find quite reasonable. Thus, accountability is achieved in a harmonious way because it boils down to the individual responsibility of updating the board. This builds transparency among team members, which in turn builds trust.


What is a slingboard (part 1)

My company, slingboards Lab, aims to provide a platform to build slingboards. A slingboard is a visual tool that guides collaboration between teammates by using sticky notes. It brings sticky notes to smartphones, tablets and the web for empowering teams to better collaborate.two-dimensional-grid

A slingboard appeals to teammates who are dissatisfied with outcomes from shared accountability. It helps teams who need better results and want more commitment from teammates. It provides teams with visual aids that align individual responsibility with teamwork.

A slingboard is a two-dimensional grid. The most important item in a slingboard is the columns because they are the ones that make it possible to visualize the workflow. The aim is to move each sticky note from column to column to accomplish the workflow. The rows are used to group and organize the yellow stickies in a logical manner. If we expect to have only a few stickies then it is possible to have a single row without any grouping.


Slingboard is great for teams that need to complete a business process. The picture above shows how to transform the workflow of a factory order into a slingboard. Each column represents a state in the workflow. A column expresses an explicit rule that transforms the collaborative work into a sequence of individual responsibility.

pinningAn important feature that simplifies the board layout is visually pinning a status tag to the sticker. This status tag is used to visualize issue that is not directly associated with the value-added steps displayed by the columns. Pinning creates visibility and awareness and allows the right people to react quickly to that new status. A visual alternative to pinning is creating special columns that fulfill the same purpose. While this is valid, and many people do it, we prefer pinning to expose that something is going wrong, or not happening. Board real estate is expensive. If you start creating special columns for each status a sticky note can have, you might quickly fill the board with empty zones.

A slingboard reduces frictions by making explicit the “invisible” knowledge. It shows information teammates care about such as:

  • It identifies the flow of work and what is being done;
  • It helps understand and indicate priorities;
  • It highlights when something is going wrong or not happening;
  • It cuts down on meetings to discuss work issues;
  • It provides real time feedback to everyone involved in the whole process;
  • It allows to see whether performance is met.

Slingboards apply to any domain. As soon as teammates need to work together to accomplish a workflow a slingboard becomes useful. Here are some examples:

  • Factory:  it can help to optimize maintenance work order;
  • Manufacturing: it can help salesmen to get involved with accounts receivable collection;
  • Recruitment firm: it can help to monitor candidate;
  • Financial institutions: it can help tracking the investment process.

(Go to Part 2)

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Changing things around

It has been over ten years that I have a personal website at “”. For several years, I have managed the content of this website using  the obsolete product CityDesk created by Joel Spolsky. Until recently the site was still promoting my consulting services. It was a simple website with few pages and no more.

Times are changing and there is something new. I finished a cycle with the forthcoming publication of my book “Executable Specifications with Scrum“. I gradually leaves consulting and moves on to other challenges. After several years with success as an agile coach specializing in architecture, I return to my first love, the entrepreneurship.  I am the co-founder of Slingboards Lab, a young start-up that helps build collaboration boards for tablets and mobile phones.

Today, I turn my website into a blog to tell this adventure. On this blog, with humility and transparency, I will describe my journey as an entrepreneur. I will tell the story of Slingboards Lab, the company that I recently founded with Erik Renaud

Obviously, besides Slingboards Lab, you will find posts that will address more specifically my book “Executable Specifications with Scrum“. I remain fascinated by software development with agile practices. Especially since I discovered many similarities between starting a business using “lean startup” and “iterative requirements’ discovery”. I will be back soon on this topic.

Thank you to accompany me. The journey looks bright.

“It is good to have an end to journey toward; but it is the journey that matters, in the end.” ― Ernest Hemingway

“There is no way to happiness, happiness is the way” ― Bouddha