channel CIO1 {
   out min(m: Int, tick) = (m + 1) % 60
}
channel HourUpdate {
   in hour(h: Int, update(h2)) = h2
   out hour_ang(h_ang: Double, update(h2)) = h2 / 6 * PI
}
channel MinUpdate {
   in min(m, update(m2)) = m2
   out min_ang(m_ang: Double, update(m2)) = m2 / 30 * PI
}
channel Clock {
   in min(m, update(m2)) = m2
   out hour(h, update(m2)) = if(m2 == 0, (h + 1) % 24, h)
}
