The application I use to make finger-joint boxes is called BoxMaker. It was originally published in Java by Rahul Bhargava. I wanted something a bit more flexible. Since he published the original Java code, I converted it to c# and made some changes. The version I made allows you to specify whether to include a top to the box or not. With a top, you get 6 sides. Without the top, you get 5 sides and a straight-line cut to finish of the top (eliminates unused finger-joints when a top is not needed). The tissue box I showed was made that way - no top (actually no bottom in this case).
[Note - The screen image below is very fuzzy - don't know why. Click on it to open and it looks fine.]
The really nice feature is that you can specify the width of your kerf (Cut Width) - which gives you really nice tight finger joints.
For the Notch Length, just let it be auto at first (you can play with it later). It does some calculations to give optimal notch size, based on the thickness of the material. Generally, you want 2-3 times the thickness.
BoxMaker creates a PDF that can be imported to Corel or most CAD packages. There were also some issues I ran into with PDF compatibility with Corel, so I changed the PDF module to a public version of PDF generator code which I further modified, also written in c#, and it now works pretty well.
Once a "box" is created, I import the PDF into Corel, add any decoration or additional cuts I want to make, and then send to the laser via my Light Object DSP. When I am satisfied with the design and the way it cuts, I simply save the DSP file and can re-run the job as often as I like with no additional setup required.
Once you start playing with this, you will find lots of ways to use it and lots of ways to modify the output to make some really nice objects. Try adding a line 2/3 the way up on the four sides of an enclosed box (with top). Add a couple of hinges and you have a nice box you can open. If you make something using this, please post it so the rest of us can see it.
The attached file is a simple installer for Windows machines - requires .Net Framework 3.5 (which nearly everyone has installed these days). After you unzip the file, run the setup. It will install for you and put a shortcut on your desktop. Even if you are on a locked down computer at your office, you should be able to install this, as it does not require any administrator privileges.
For those using a Mac or Linux, you can get the original version (without my modifications) at
http://www.rahulbotics.com/personal-projects/boxmaker/. There is also an original java Windows version there, if you don't want to use mine.