loose notes
there's the family of shapes which end in "GCD" shapes (AADGCD, CGDGCD, DADGCD) there are the shapes that end in "GAD", et cetera. ---
'Nashville' tuning
The 6th, 5th, 4th and 3rd strings are replaced with lighter strings so they may be tuned an octave higher. The 6th and 5th strings are wound, the rest are plain.
6th string: E - one octave higher 5th string: A - one octave higher 4th string: D - one octave higher 3rd string: G - one octave higher 2nd string: B - normal pitch 1st string: E - normal pitch
Billy Gibbons in some old guitar magazine talked about a fake 12-string tuning, "Cheater's 12": "You use a first string in place of the big E and tune it in unison to your little E. Then you use a second string for the fifth, and tune it to an A. Use another second string for your usual fourth string, tuned to a high D. So you've got standard tuning, but a strange octave effect.
David Gilmour uses , something close to Gibbons' variant for Hey You (on The Wall). He uses unwound strings across the fretboard, replacing the 6th string with a high E string -- tuned to the normal pitch for the 1st string (two octaves above the normal pitch for the 6th string).