I used about 20 feet each of black, olive drab, and tan paracord, to tie this long 2 bight turks head knot, with 59 leads, on a cane my dad got from the VA hospital. It's an early Father's Day present. I left the knot work spread out a bit since it's an adjustable height cane, and the button/slots are still accessible.
The 2 bight turks head knot is not hard to tie, but a long one can take a couple of hours or more to make the additional passes, keeping it straight, and working the slack out. The link shows a 2 bight turks head and how to increase it to a 4 bight knot.
A smaller turks head knot was tied over the start/finish of the 2 bight knot, at the cane handle, to help cover the trimmed ends of the spaced out knot.