Here we will consider some complexity issues related to rearrangements, and show that for a wide range of rearrangement types, the size of the space of possible structures scales approximately as (2x)^(n(n-1)/2), where x are the number of breakpoints formed by each rearrangement and n is the number of rearrangements that take place. We also show that many clusters of rearrangements cannot be explained by standard rearrangements, but may be explained by break induced replication.