T Rex
20th Century Boy

Ok there are four main riffs to this

Intro Riff

G------------------------------------------------------------------------
D------------------------------------------------------------------------
A------------------------------------------------------------------------
E—0-0----0-0----000-0-3-0-3-0-3-0----------000-0-3-0-3-0-3-0-------------

G------------------------------------------------------------------
D------------------------------------------------------------------
A------------------------------------------------------------------
E—000-0-3-0-3-0-3-0-------000-0-3-0-3-0-3-0------------------------

Verse Riff

G----------------------------------------
D----------------------------------------
A----------------------------------------
E—5--5555--35--5555--35--5555555555555---

G-----------------------------------------
D-----------------------------------------
A-----------------------------------------
E—0-0-3-0-3-0-3-0---000-0-3-0-3-0-3-0-----

Chorus Riff                                                       Followed by this on the first chorus

G---------------------------------------------------  -----------------------------------------------
D---------------------------------------------------  -----------------------------------------------
A---------------------------------------------------  -----------------------------------------------
E----5—5—5—55—777-7---00-0—00-0--------------------  -000-0-3-0-3-0-3-0---000-0-3-0-3-0-3-0---------

Bridge Riff

G-----------------------------------
D--------------------5--------------
A—7---5-7-------7------7------------
E-----------------------------------

The order goes
Intro x1
Verse x2
Chorus x1 (with extra ending)
Verse x2
Chorus x1 (without extra ending)
Bridge x4
Verse x2
Chorus x1 (without extra ending)
Bridge x4 then there is a small outro but it is just mainly played on A7