http://www.fontsmith.com/fonts/fs-jack

It was a forensic examination by Jason Smith of his existing designs that laid the groundwork for FS Jack. Jason made a list of unique characteristics that would give the sans serif font its typographic thumbprint, which included an unusually large x-height and slightly off-the-wall letters like the lower-case “a”, “g”, “k” and “y”. “I wanted to make something that was slightly uncomfortable,” says Jason, “and in doing so simplify the quirkiness down to a few letters.” Fernando Mello did “the rest of the cooking”, filling the design out and making the additional weights.