########
# Could extend this to draw from camera with:
#   Wish $this has thumbnail grid with 8 frames and 4 columns
#   When $this has thumbnail grid /thumbnails/ {
#     Wish $this draws $thumbnails; # Would need to query $thumnails for its frameCount and columns
#   }
#######

# - path get prepended with ~/folk-images/
When /anyone/ wishes /p/ draws sprite /path/ with /frameCount/ frames and /columns/ columns {
  set im [image load $path]
  set sheetwidth [image width $im]
  set sheetHeight [image height $im]
  set spriteWidth [/ $sheetwidth $columns]
  set rows [/ $frameCount $columns]
  set spriteHeight [/ $sheetHeight $rows]

  When the clock time is /t/ & $p has region /r/ {
      set frameNumber [expr {round ($t * 60 / $columns) % $frameCount}]
      set x [* [% $frameNumber $columns] $spriteWidth]
      set y [* [% $frameNumber $rows] $spriteHeight]

      set subimage [image subimage $im $x $y $spriteWidth $spriteHeight]
      set center [region centroid $r]
      set angle [region angle $r]
      Wish to draw an image with center $center image $subimage radians $angle
  }
}

Claim $this has demo {
  Wish $this draws sprite $path with 8 frames and 4 columns
}