All strands written 5' to 3'

RE1     'CGTATTGGACATTTCCGTAGACCGACTGGACATCTTC'
RE2     'CCTCACCTTCACACCAATACGAGGTA'
RE3     'TCTACGGAAATGTGGCAGAATCAATCATAAGACACCAGTCGG'
RE4     'CAGACGAAGATGTGGTAGTGGAATGC'
RE5     'CCACTACCTGTCTTATGATTGATTCTGCCTGTGAAGG'
SE1     'CTCAGTGGACAGCCGTTCTGGAGCGTTGGACGAAACT'
SE2     'GTCTGGTAGAGCACCACTGAGGCATT'
SE3     'CCAGAACGGCTGTGGCTAAACAGTAACCGAAGCACCAACGCT'
SE4     'TGAGGAGTTTCGTGGTCATCGTACCT'
SE5     'CGATGACCTGCTTCGGTTACTGTTTAGCCTGCTCTAC'
UE1     'CGTTAAGGACGACGCAATTCTCACATCGGACGAGTAG'
UE2     'CCTCATGGTTTCACCTTAACGAGGTA'
UE3     'AGAATTGCGTCGTGGTTGCTAGGTCTCGCTATCACCGATGTG'
UE4     'ACCAGCTACTCGTGGATCTATGGTAT'
UE5     'ATAGATCCTGATAGCGAGACCTAGCAACCTGAAACCA'
VE1     'CCATTCGGACGTTTGCGGTAAAGATTAGGACATTGAA'
VE2     'CTGGTTCCGAGCACCGAATGGATACC'
VE3     'TTACCGCAAACGTGGCGAGTGTGATACGACTACACCTAATCT'
VE4     'TGAGGTTCAATGTGGCGTTCATACCT'
VE5     'TGAACGCCTGTAGTCGTATCACACTCGCCTGCTCGGA'
SE1J    'CTCAGTGGACAGCCTACTTACCTTTTGGTAAGTATTGTTCTGGAGCGTTGGACGAAACT'
SE5J    'CGATGACCTGCTTCATGTCGGCTTTTGCCGACATTTGGTTACTGTTTAGCCTGCTCTAC'

Here are the structures of the 4 double crossovers.
Each is labeled in the center section, RE, SE, UE, or VE. 
I have put > on the 3' ends. The manner in which the hairpins are
drawn for SE15J don't reflect any structural knowledge, we think they
just flop around. 

ans =

      CGTATTGG----ACATTTCCGTAGA----CCGACTGG----ACATCTTC>     
<ATGGAGCATAACC\  /TGTAAAGGCATCT   <GGCTGACC\  /TGTAGAAGCAGAC
               ||       RE                  ||              
 CCTCACCTTCACA/  \GGCAGAATCAATC----ATAAGACA/  \GGTAGTGGAATGC>
     <GGAAGTGT----CCGTCTTAGTTAG----TATTCTGT----CCATCACC     


ans =

      CTCAGTGG----ACAGCCGTTCTGG----AGCGTTGG----ACGAAACT>     
<TTACGGAGTCACC\  /TGTCGGCAAGACC   <TCGCAACC\  /TGCTTTGAGGAGT
               ||       SE                  ||              
 GTCTGGTAGAGCA/  \GGCTAAACAGTAA----CCGAAGCA/  \GGTCATCGTACCT>
     <CATCTCGT----CCGATTTGTCATT----GGCTTCGT----CCAGTAGC     


ans =
              TTTT  
               \ \
                C G
                 C G
                  A T
                   T A
                    T A  
                     C G
                      A T
                       T A
                       | T
                       | T 
                       | / 
      CTCAGTGG----ACAGCCGTTCTGG----AGCGTTGG----ACGAAACT>     
<TTACGGAGTCACC\  /TGTCGGCAAGACC   <TCGCAACC\  /TGCTTTGAGGAGT
               ||       SE15J               ||              
 GTCTGGTAGAGCA/  \GGCTAAACAGTAA----CCGAAGCA/  \GGTCATCGTACCT>
     <CATCTCGT----CCGATTTGTCATT----GGCTTCGT----CCAGTAGC     
                                    / |
                                    T |
                                    T |
                                     T A
                                      A T
                                       C G
                                        A T
                                         G C
                                          C G
                                           C G
                                            G C 
                                             \ \
                                             TTTT                   
ans =

      CGTTAAGG----ACGACGCAATTCT----CACATCGG----ACGAGTAG>     
<ATGGAGCAATTCC\  /TGCTGCGTTAAGA   <GTGTAGCC\  /TGCTCATCGACCA
               ||       UE                  ||              
 CCTCATGGTTTCA/  \GGTTGCTAGGTCT----CGCTATCA/  \GGATCTATGGTAT>
     <ACCAAAGT----CCAACGATCCAGA----GCGATAGT----CCTAGATA     


ans =

      CCATTCGG----ACGTTTGCGGTAA----AGATTAGG----ACATTGAA>     
<CCATAGGTAAGCC\  /TGCAAACGCCATT   <TCTAATCC\  /TGTAACTTGGAGT
               ||       VE                  ||              
 CTGGTTCCGAGCA/  \GGCGAGTGTGATA----CGACTACA/  \GGCGTTCATACCT>
     <AGGCTCGT----CCGCTCACACTAT----GCTGATGT----CCGCAAGT