who knows what the two signals are ?
https://www.youtube.com/watch?v=-tMNQ_h817s&list=LL8Hl4wSKvUUL8qKlFE4P0Zg&index=3&t=1s
https://www.youtube.com/watch?v=0Glpgt2A_Ak&list=LL8Hl4wSKvUUL8qKlFE4P0Zg&index=4
https://www.youtube.com/watch?v=-tMNQ_h817s&list=LL8Hl4wSKvUUL8qKlFE4P0Zg&index=3&t=1s
https://www.youtube.com/watch?v=0Glpgt2A_Ak&list=LL8Hl4wSKvUUL8qKlFE4P0Zg&index=4
