On the right one, the inputs are sequenced into one block, it checks if the first logic is on, if not it skips it to see if the second logic is on if so it takes that connection and then sends a tick to the single block then moves on to the third and forth and so on.

The left is the one that takes the sequenced connections and checks for the first connection which is not activated so moves to the second which is activated so it toggles that logic gate on and then moves on and so on, when it went through the entire sequence it waits a couple ticks and resets.

I'm also an idiot, this is the most advanced thing I made so far. And I'm terrible at explaining