The catamaran is pretty complex base form. But from this form is very simply to fold pajarita and some kusudams. At the first and third stage precrease the blinz base. On the second - simply marks vertically and horizontal middle of the square.

Since the fourth stage, we begin actually to fold the base form. Let's fold the left and right sides of the square to the middle. Then we shall do same with the top and bottom parts.

Now, slightly opens the model, and shall extend from it four corners. The catamaran is ready.

On this base form is based the author model: the dog.