[lofties]

Excellent article! Well written and the animations make it so much easier to understand. However I was unable to get the loops to go.

[leereeves]

I was able to consistently start a loop in one click by clicking on the edge between grey and white (slow and fast refractory) cells ASAP after a normal beat.

If I'm fast enough, the wave can't spread to the grey cells so it only goes in direction around the red cells and starts a loop.

(But you can't do this on the first image with a Defibrillate! button because there are no slow cells.)

[samwho]

I was able to do it by clicking in a few places in quick succession evenly spread out.

[jcattle]

Try clicking in one place repeatadly and adjust clicks slightly to always go next to the fastest refractory cell possible. This works like a charm to induce arrhytmia