Rollover Relief

Delays taxation when a capital gain is realised, usually when the owner had little choice (such as a building being destroyed in an earthquake and replaced on insurance) or there is a social reason the concession is seen to be fair.
Example:
If a building is destroyed in an earthquake, insurance pays more for its replacement than it was originally purchased for, and a new building built—there’s no immediate tax, but the rise in value is considered for calculating the tax when the property is eventually sold.
Visual idea: Coins rolling over a calendar.