Distributed systems algorithms : simplified explanation

Cristian's algorithm:
I send you my time
You get it and record your own time
You send me back the time you recorded it and the time you send back
I record the time I receive it

me -(T1)> you
you -(T2,T3)> me
me -(T4)> me

Berkeley Algorithm:
Teacher shouts out what time is it
Kids reply with their own time
Take average and tell kids to follow this time