12 F In The D

[PB57]

12 F in the D

[bluebell56]

PB57. Don't forget you can add to your original post. No need to do separate ones.

[JJ109]

This is probably too obscure to be correct but...

12 Finger-widths in the Duodenum

The duodenum (from Latin duodecim, "twelve") is the first part of the small intestine, that is about twelve inches (30 cm) long. More precisely, this section of the intestine was measured not in inches but in fingerwidths. In fact, in German the name of the duodenum is Zwölffingerdarm, in Dutch the name is twaalfvingerige darm and in Bulgarian the name is дванадесетопръстик, all meaning "twelve-finger bowel".

[Hazlinny]

Another quite obscure one - 12 faces on a Dodecahedron - but it's not "in the",