Two variables influence each other. Click the + or − to change whether each influence amplifies or dampens. Watch how the system behaves.

Connections
A → B
B → A
Loop type: Reinforcing (+ +)
Presets
Reinforcing Loop
Both connections amplify. More A leads to more B, which leads to more A. Runaway growth (or collapse if values go negative). Examples: compound interest, viral spread, arms races, bank runs.