This is a simplified picture of the system dynamics of an RBMK nuclear reactor highlighting its design flaws. Two reinforcing feedback loops and one negative loop, along with significant human disregard for safety led to the events of April 1986.

For an entertaining, albeit inaccurate at times, presentation, watch the HBO miniseries clip on YouTube: https://www.youtube.com/watch?v=TmIEI4ky-Zc

Try: Tools > Identify Loops to see details.

Having a paid off house can feel secure, but home equity may be an expensive way to fund housing, compared to having a mortgage, or renting and saving the difference. This simulation compares the TCO (total cost of ownership) for renting and buying over a realistic time horizon.