Counting Penrose tiles
count_demo
Response time from GeoGebra's server to this applet is more than 1 minute.
With default settings you may receive an Unresponsive script warning from Firefox.
I've set the value of dom.max_script_run_time from 10 to 100 (Firefox 48.0.2) and it works well.
See: https://support.mozilla.org/en-US/kb/warning-unresponsive-script