Nodes have 4 Activation Modes, according to which Resources get redistributed.
A Node in a Machinations diagram can be in one of 4 different Activation Modes:
Automatically - fires every Time Step. All automatic Nodes fire simultaneously.
Interactive - fires only when the you click it during Run time.
Starting Action - fires only once, immediately after you click the Run button.
Passive - can fire only in response to a trigger generated by another element.
Here's a video example of 4 Pools, having different Activation Modes, and their actions (or lack thereof).
The green Pool is Automatic, and will push 1 Resource every time step, until there are no more Resources available.
The orange Pool will push a Resource once, when you hit the Play button.
The blue one is Interactive, and will only push a Resource when the Player/User clicks on it.
The red Pool is passive, and it will not react in this case.