This design looks great in a paper with different colours on each side. A 6" inch square is needed.
A lot of pre-creasing is recommended for this one, I will show it all. Precreasing means folding, creasing sharply, and unfolding to make a crease that will easily fold back later.
Precrease along both middle lines.
Precrease diagonally both ways.
Fold in all the corners, crease and unfold.
Fold in the sides to meet the middle lines, unfold.
This is all the precreaseed lines:
Preparation: DONE.
Collapse the sheet into the following catamaran shape.
The main colour of the finished piece is the inside colour.
Another view of the base:
Base from the outside:
Collapse it flat (the two keels point away from eachother):
Lift the corner and pull it out, as below:
Repeat on the other side:
What it looks like if you turn it over:
Lift a corner and open it.
Squash it down:
Repeat on the other corners:
This is the shape you get:
The following picture shows the different steps of the corners that follow now.
Clockwise from noon:
Fold the corner in,
repeat on both sides.
Open it up and put the fold you just made inside it
Repeat on both sides.
This is the shape you have now:
Lift the flaps you made in the previous step up and out.
Lift the corners in the middle up and fold them out. Crease well.
Leave about 1mm to the visible crease on the pointy flaps.
Fold the points back down, possibly secure them with a drop of glue or tape.