1-8
: 1s cast to bottom followed by 2s+3s+4s (who dance up to start); 1s make
  arch, 2s+3s+4s dance up under arch.  2 3 4 1
9-16
: 2s make arch, 1s dance up under arch & cast back to 4th place
17-24
: 3s+4s (middle couples) circle 4H round & back, finishing turning
  inwards, 3s face up, 4s face down
25-32
: 3s & 4s dance out of ends & cast back to same place; All turn RH (or
  birl).  2 3 4 1