25w37 Learning PWM using Oscilloscope

We continue with Team A for the Analog Output and PWM learning, it's fun and efficient learning this week, thanks to a student's spontaneous support, we have a digital oscilloscope with us, and we all together observe how the signals are changed in the good visualization. Oh, we also have a student actively trying his own ideas to generate PWM by hand-made method, using digitalWrite() with controlled time delay between HIGH and LOW, instead of analogWrite().