I can only try-
Let me get you started-
There are two variables to keep in mind:
1. The distance between the center of the dropped pencil to the closest line, let’s call this variable “x” and
2. The acute angle between the pencil and the pencil and all the lines (since they are parallel). Let’s call this variable “y” (since I don’t know how to get the Greek Letter “theta” on my keyboard).
The variable “x” can take on values between 0 and 1/2 (recall that the distance between stripes is 1 and the width of the line separating the stripes is negligible).
The variable “y” can take on values between 0 and 90 (in degrees, any angle 90 degrees and above is not acute).