Hi community, This is my first post, so I'm sorry for any mistakes in style. I have also posted this question on StackOverflow: http://stackoverflow.com/questions/42920777/boost-msm-parallel-behavior-with.... I am using Boost MSM (basic and functor front-ends) and am trying to implement the following state machine (https://i.stack.imgur.com/K79qk.png): enter image description here I am using Boost MSM (basic and functor front-ends) and am trying to implement the following state machine: enter image description here In words: 1. Enter state State1 2. Enter state A and execute action_A. After 2 seconds, print "Trying again..." and re-execute state A (i.e. call its entry action). This loops forever... 3. At the same time as 2 (i.e. "in parallel"), enter state B and execute action_B. After 5 seconds, print "Trying again..." and re-execute state B (i.e. call its entry action). This loops forever... I would like to know the way to create this state machine in Boost MSM. There are two tricks here which I cannot figure out how to do: - Execution in parallel (i.e. running action_A does not stop running action_B at the same time) - Delayed transition (i.e. the transitions which happen after 2 seconds for state A and after 5 seconds for state B). Neither delay should be blocking! The transitions should just "fire" after this time. Thank you very much for helping, Danylo.