1. Does the first highlighted speech meana) I form the rest of the sounds by changing the shape of this aperture or by this rubber bell or by...
or
b) I form the rest of the sounds by changing the shape of this aperture, I mean this rubber bell you see here, or by...
or
c) I form the rest of the sounds by imitating human aperture or by this rubber bell or by...
or
d) I form the rest of the sounds by imitating human aperture, I mean this rubber bell you see here, or by...
2. Does the second highlighted text mean "considering that the first version of your machine was made up of fireplace bellows and a bagpipe reed, this new version is much more improved and complicated"?