I figured out a glitch in blue sphere stages that it's possible to turn blue spheres into rings without surrounding them completely with red spheres. This can be done with any 3x4 or larger formation of blue spheres but practically it's useful with most 4x4 or larger formations.
Stages that can be improved with this glitch include at least S3 stages 1, 2, 3, 4, 6 and S3&K stages 1, 3 and 7. The most notable improvement will be in 4th S3 special stage where the large formation of blue spheres can be turned into rings by collecting only 11 spheres, making it nearly 5 seconds faster than conventional way. Time saves on other stages range from a couple of frames to a few seconds.
It does not matter from which direction the last sphere is collected so in these images it's collected from the angle that gives best view:
Huge thanks to mike89 (mike89sda) for showing this variation of this glitch in his stream which made me research this subject quite a bit more:
Below are ascii representations of the glitch in case the images will be removed in the future.
Legend:
X = red sphere
. = blue sphere
o = bumper
# = blue sphere, collect this next to turn all remaining touching blue spheres into rings.
There are several ways to trigger the glitch.
First main method is to turn 3x3 area completely red and then collect 2 adjacent blue spheres from a corner:
.#X
XXX
XXX
XXX
This also works if there are more touching blue spheres remaining, for example all in the following formation will turn into rings:
.....
...#X
..XXX
..XXX
..XXX
The centermost sphere can even be a bumper:
..#X.
.XXX.
.XoX.
.XXX.
.....
Second main method is to surround an area of blue spheres but leave one corner "open" (the blue spheres in the middle must not form a rectangle because then only that rectangle would turn into rings and not the outside area):
.XXX
#X.X
X..X
XXXX
Or more blues remaining in the middle and/or outside (also works if there are any bumpers in the middle):
..XXX
.#X.X
.X..X
.X..X
.XXXX
http://dehacked.2y.net/microstorage.php/info/644260335/S3%20special%202%20improved.gmv
Special stage 2 begins around frame 7800.
S3 special stage 6:
143 frame (140 + 3 on ring bonus) improvement by completely new route.
The new route is about 20% longer than the current TAS (about 211 paces vs 174 paces) but takes 38 turns less (46 vs 84) and takes most of the turns before running speed goes up.
http://dehacked.2y.net/microstorage.php/info/1705518723/S3%20special%206%20improved.gmv
Special stage 6 begins around frame 40000.
S3 special stage 7:
21 frame improvement by turning on a red sphere near the end. I wonder if this strategy is prone to desyncs though delaying the movie start by one frame still synced perfectly.
http://dehacked.2y.net/microstorage.php/info/562531663/S3%20special%207%20improved.gmv
Special stage 7 begins around frame 48600.