REQUEST: thin circles of all sizes

I'm trying to get together a sort of "French curve" of usable elements
for doing ascii art. The problem is that a real French Curve can be
turned, while ascii curves can't, so I'm just looking for different
sized circles, done with a thin line, that I can take apart and use to
make other drawings. Here is an example of the thickness of the line I
am looking for:

               ._r=/~~~~~~~~\=\_
            .//~                ~+\,
          j/'                      ~+_
        j/'                          `+,
      .Z'                              `N,
     jf                                  \,
    j!                                    !;
   d!                                      !;
  :!                                        !;
  /                                          V
 d                                           `b
 |                                            |
|'                                             |
W                                              b
#                                              V
P                                              |
|                                              |
M                                              d
|                                              |
!;                                            :!
 W                                            /
 !;                                          .!
  \,                                        .Z
  `N                                        /'
   `t                                      d'
    `t                                    Z'
      \,                                ./
       ~\                             ./'
         Y\,                        ./f
           ~=_                    _=~
              ~+\_,          ._/+~
                  `~~\====~~~'

And here is an example of a line that is a little thicker than I would
like:

               .,ad88888ba,.
            .o8P"'      ``"Y8b.
          .dP'               `Yb.
         .8|                   |8.
         d8                     8b
         88                     88
      .,a888888ba,.     .,ad888888a,.
   .o8P"'`8|   ``"Y8b.o8P"'    |8'`"Y8b.
 .dP'     `8b.     .d8b.     .d8'     `Yb.
.8|         `Y8b,,,8| |8,,,d8P'         |8.
d8            ``"Y8888888P"''            8b
88                88   88                88
Y8                Y8   8P                8P
`8|               `8| |8'               |8'
 `8b.              `888'              .d8'
   `Y8b,,       ,,d8P~Y8b,,       ,,d9P'
     ``"Y8888888P"''   ``"Y8888888P"''

Unfortunately I don't have the credits for those drawings. I got them
off alt.ascii-art shortly before the creation of rec.arts.ascii.

Thanks a lot!

Zack