The Pinterest bloom gif is one-way (bud → full rose on black), so a
plain loop snaps. Four loop treatments now sit in visuals/scenes/,
auditionable live by swapping the header directive (ctrl+s reapplies):

  rose_bloom          ping-pong at half speed, mci-interpolated —
                      the rose breathes open/closed over ~13.5s (default twin)
  rose_bloom_fast     ping-pong at native speed (~6.8s cycle)
  rose_bloom_rebloom  seam-crossfade: blooms again every ~2.5s
  rose_bloom_noir     fade through black, cinematic gap

Recipes (ffmpeg): ping-pong = split+reverse+concat with boundary frames
trimmed; slow = setpts 2x + minterpolate mci; rebloom = xfade against
itself, trim [fade, offset+fade]; seams verified by first/last-frame
RMSE (0.028 = codec noise for the ping-pongs).

Source renamed to ~/Downloads/rose_bloom.gif (stable stem for the
twin lookup).