Typeface that lets you try different sets

Ok ok, ok, this is really bugging me. I saw a tweet the other week with a link to a site for a new typeface that lets the user choose stylistic sets and then view said font in mock ups ect. and now I can't for the life of me remember which foundry released it. It was a very intuitive site, and had a really nice structure. Super simple UX. ...

It had the entire alphabet, and you simply switched a letter (like two story a into single story a) or chose to have ink traps ect. etc...... I was trying to show it to one of my friends and I was stumped because I forgot the name of the foundry that released it..... 

 I need to start writing more things down.....