There is evident topological difference between three important types of reactions in heterocyclic chemistry:

In heterocyclizations a cycle is formed from a chain:

In heterocyclic ring opening reactions a chain is formed from a cycle:

And in recyclizations the cycle is formed from another cycle:

The chain may be an intermediate of a recyclization, and the process would be better represented by a dragon rather than by a snake:

Pictures are taken from Ref. [12]