122 OUR PHYSICAL WORLD 



from the corners along these lines to within a half-inch of the 

 intersecting lines. Lay the left hand, back down, on the paper, 

 the fingers about at the center. With the right hand fold in any 

 one corner and hold it with thumb and finger of the left hand. 

 In the same way fold in every alternate corner around the square, 

 and when all are in hand run a pin through the four infolded 

 corners and also through the center of the square. Thrust this 

 pin into a wood handle and the windmill is complete. 



An eight-point windmill may be made in place of the four- 

 point, as follows: It makes the mill more attractive if paper of 

 two colors is used. Cut a 6-inch square of paper of each color, 

 and cut in from the corners as before. On one paper make a 

 half-inch cut at the inner end of each diagonal cut on the left- 

 hand blades, making it at right angles to the edge. Lay this 

 square upon the table, the second square upon it so that the 

 centers coincide and so that the corners of the upper sheet are 

 midway between the corners of the lower sheet. Then insert 

 each alternate edge of the upper blades into the cuts on the lower 

 blades. Then fold over all the inner points as before and run 

 the pin through them and through the centers of the two sheets. 

 Stick the pin into a handle. 



To make the wooden windmill, cut two 8-inch lengths of wood 

 | inch square. Find the middle of each piece and mark a cross- 

 line at this point. Draw two lines parallel to this, one at each side 

 of it, T V inch distant from it. Saw into the strip on each of these 

 two lines, cutting halfway through the strip. Cut out the central 

 block. The two strips may now be put together at right angles 

 to each other, the space formed by cutting out the block fitting 

 over the remaining section of the other stick. See that they fit well. 



With a knife shave off the opposite angles of one arm until a 

 thin blade of wood is left. The central region is not cut away, 

 but bevels on the thin blade. Cut each of the other arms in the 

 same way, so that the blades are inclined in the same direction. 

 Fasten the mill thus formed securely to a cylindrical stick some- 

 what larger than a pencil. 



