{"type":"rich","version":"1.0","title":"[V3, Animation] Writing out Knuth's up-arrow notation in terms of powers","html":"<iframe src=\"https://www.desmos.com/calculator/r4oc3imgo8?embed\" width=\"500px\" height=\"500px\" style=\"border: 1px solid #ccc\" frameborder=0></iframe>","width":500,"height":500}