This is a Card we made at my October retreat. Everyone loved it and came up with lots and lots of designs of their own! What is nice is the DSP actually helps design the card and all you need to do is fill in the little box and add a sentiment.
There are some wonderful Utube videos out there that take you step by step through how to make an Impossible Card, so instead of me trying to reinvent the wheel, just Google Impossible Card to find the directions. The legs on this card are cut at one inch. For a wider leg, cut at 1 1/4 inches. That will make a smaller text box though. Below is the back of the card. Try these! They are addictive!