brain-even: https://asciinema.org/a/F61X2DtIrLCeDckRHy1RquQcI
brain-calc: https://asciinema.org/a/KaT0QvumuSVwcRSGcMvRNg5aW
brain-gcd: https://asciinema.org/a/VWVhXA7IlLWEzPUPru63RC6UL
brain-progression: https://asciinema.org/a/3vq8Rgf8oJBm4i8sRP4qs0wRa
brain-prime: https://asciinema.org/a/NmyZtx9zd5y5EqvLuaw35o2uy