Let's make simple things look beautiful. Just because the LCD shows frequency doesn't mean the numbers and text need to be of a plain, boring font.
Most of us, especially me, while working with electronics need something to tell us what the frequency of a square wave or PWM signal in a board is. This is especially true when you are fixing it (those who work with electronics/hardware maintenance will understand exactly how important this is).
In this project we used a digital clock, with 2 fonts for numbers that were created for such a clock.
This project uses interrupts to get accurate time reading. It also used the Math.h Library for inf case, and TimerOne Library for display values every second for a more stable reading on the display.
We used INT0 (Pin 2 In Arduino) as an input interrupt. As a test, I used PWM Pin in the Arduino as input.