OSX 10.12.5
Firefox 62.0.2 64bit
I used Patternarium a couple of days ago and all was working fine, my system hasn't changed but i'm seeing this when I visit the same page today.
Patternarium works fine in Chrome but not Firefox.
Any thoughts ?

Looks like your Firefox is blocking Flash from saving data. Make sure that website and global settings for Flash is set to allow us to store the Patternarium information.

Flash Website Storage Settings panel:
http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager07.html

Global Storage Settings Panel:
http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager03.html