Unusual trade bys.

sdr> /program=Program.A2
A2
sdr> heads pass thru ; trade
| 4G<  1Gv  1Bv  2B>
| 
| 4B<  3B^  3G^  2G>
sdr> /// t-boned trade by
sdr> trade by
| 4B>  3B^  3G^  2G<
| 
| 4G>  1Gv  1Bv  2B<
sdr> heads do half of a trade while the sides u-turn back
|      3B>
| 4B<       2G>
|      3G<
| 
|      1G>
| 4G<       2B>
|      1B<
sdr> trade by
| 4G>  3G<  3B>  2B<
| 
| 4B>  1B<  1G>  2G<
sdr> veer left
| 4G>  3B>
| 
| 4B>  1G>
| 
| 3G<  2B<
| 
| 1B<  2G<
sdr> fan the top
| 1B^  4B^  3Gv  4Gv  2G^  1G^  2Bv  3Bv
sdr> as couples ends cross fold
|           4Bv  1Bv
| 
| 3Gv  4Gv  2G^  1G^
| 
| 3B^  2B^
sdr> as couples star thru
|      1G<
| 
|      2G<
| 
| 3B>  4B<
| 
| 2B>  1B<
| 
| 4G>
| 
| 3G>
sdr> girls trade
|      1G>
| 
|      2G>
| 
| 3B>  4B<
| 
| 2B>  1B<
| 
| 4G<
| 
| 3G<
sdr> /// trade by from triple boxes.
sdr> trade by
|      2G<
| 
|      1G<
| 
| 4B<  3B>
| 
| 1B<  2B>
| 
| 3G>
| 
| 4G>
sdr> /exit