Producing Square Signal with Proteus Electronic Simulation Application

Hello friends.
I will tell you about the Proteus application, which is an electronic simulation. With Proteus application you can create and test electronic circuits in virtual environment. This gives us the opportunity to test the system we will actually create. I will tell you how to use this application. I'm going to design a circuit that produces a square signal in this videom. When the circuit is designed, the lights will flash.
I hope that will be useful.