All you need is a vector graphics editor such as Inkscape, Adobe Illustrator, CorrelDRAW, etc.
Inkscape is free.

Step 1: Find a Graphic

Find a black and white vector graphic or draw one yourself in Inkscape.
OpenClipart.org has lots of images http://www.openclipart.org/tags/b_w

Step 2: Elephant

How about this elephant!
Right click and download the file as an .svg

Step 3: Open It in Inkscape

After you open it in inkscape resize it to 3.5"x5.5 so it can fit in a free sample from Outfab.com
Draw a box around it and make sure you set the line color to RGB 0,0,255 and width under 0.3pt as specified in the guidelines page

Step 4: Edit Box

Round the edges by grabbing and pulling on the top right corner where the little red dot is.

Step 5: Chop It Up!

Cut it with the bezier tool or use shapes to add and subtract the joints.

Step 6: Submit It!

Go to Outfab.com and submit your file to be laser cut.
You are done with your FREE laser cut puzzle!
All you gotta do is wait for it to arrive in the mail.