There are several official versions of this composition:
the original live album recording from 1983 (and excerpts of it)
two slightly different live recordings of Rare Bird from 1986
two short remixes from 1996
a remix of Polish Dance from 2000 (alleged to be a live recording)
two slightly different live recordings of Rare Bird from 2007
a remix of Rare Bird from 2008 (alleged to be a live recording from 1988)
For convenience of reference, the composition Tangent is virtually indexed for this discography at four points. These sections are entitled as follows:
00:00 - Tangent(Section 1) 3:51
03:51 - Tangent(Section 2) 6:07
09:58 - Tangent(Polish Dance) 5:54
15:52 - Tangent(Rare Bird) 4:07
The original version of Tangent consisted of two parts, interrupted by applause and a short silence: the main part (consisting of sections 1 to 3) and a four minute encore, later entitled Rare Bird. Section 3 was later entitled Polish Dance.