[![enter image description here](https://i.stack.imgur.com/mpbH5.png)](https://i.stack.imgur.com/mpbH5.png)
Above are the illustrations, below in the red box is the QUESTION
'$a$' and '$b$' are the length of the lines as shown in the figure. The two lines are divided into '$n$' equal parts and lines are drawn according to the illustration. The curve formed by the intersection of those lines is the curve with blue stroke. $\theta = \text{Angle between the two lines}$