TEN LITTLE FINGERS - Arvind Gupta

GEOMETRY BY PAPER FOLDINGMost of these Geometric Exercises in Paper Folding have been inspired by abook of the same name, written by an Indian mathematician in 1893.His name was T. Sundara Row (anglicised from Rao).Ninety Degree angleForty Five Degree angle1. We will start with simple angles. A straight edgeis 180 degrees. If we double a straight edge uponitself we get two ninety degree angles.2. A forty five degree angle is got byfolding any right angle corner into half.Sixty Degree angle3. How to fold 60 degrees ? Divide a straight edge (180 degrees) into three equal angles. Take apoint mid-way on the straight edge of paper lift both edges of the paper from this point and foldthem to approximately 60 degrees. Before creasing ensure that the edges are flush with the folds tobe creased.Thirty Degree angleFifteen Degree angle4. Fold the 60 degree angle such that its oneedge doubles on the other. 60 will be dividedinto two 30 degree angles.5. A fifteen degree angle can be got byhalving the 30 degree angle. This can bedone by doubling its one edge on the other.PAPER DIAMONDS1. First fold asheet ofrectangularpaper into half.2. and theninto quarter.3. Fold a triangleat the left-bottom,four fold comer(the centre of thepaper).4. On openingone layer youwill see half ofthe diamond.5. Open fully to see anelegant rhombus in themiddle of the paper.6. If you make several parallelcreases at the four fold cornerthen ...7. On opening you will see a diamond in a diamond in adiamond - a series of nesting diamonds or rhombuses.