Pinwheel Model Step 4

Pull the fourth side all the way out, and crease it diagonally in the center of the model, so that it overlaps the first triangle you made.

 Valley fold the square below (in the center of the model) it in half diagonally, so that the square covers the first triangle you made.
 

Finish the third side, which will create the fourth side, in the wrong place and backwards.

 Complete the third edge now, forming the triangle like before, and a backwards triangle over the first triangle you made.
 

Fold the last side into position through the middle of the model.

 The fourth edge is complete, just in the wrong position. Valley fold through the center diagonally to put the last edge in the correct place.
 

The first known paper pinwheel originate in Europe where baptism certificates were folded into this unique shape during the 1800's.

 Your completed pinwheel should be tacked to a stick or dowel, and given to a happy child for best results.