Oh dear. It looks like the script is not supported in your current browser.
You may be able to use a different browser. This app is designed for ES6, supported in current versions of any of the following:
If you are using one of those and still seeing this message, and that includes Windows XP–8.1 and Puppy Linux users, please send an email about it to: devel at sapphirepaw.org
Squares per Block