This photo was taken part-way through the build. It shows one of the two carriers and its surrounding track - there are 9 x 90s in that and 10 x 90s in the carrier itself - on this level. There are two levels and another carrier and its track, so (9 + 10) x 4 = 76 x 90s altogether here. Add in some more at the top of the braider to reach 84 in total!

Each carrier must have an odd number of forks - I have been able to use five here, thanks to 5/10-hole Faceplates from Exacto.