[1] Figure 3.14 on page 56 of CRC & HD DNA book, Edition 2

   In p.56 Figs. (c) and (d), the 36 degrees twist angle is helical twist,
   which corresponds ~34 degrees of step twist angle as given in CEHS. For
   Figs. (a) and (b) the two twists are identical.

   p56figab/p56figcd are two short shell scripts for getting figures (a)/
          (b) and (c)/(d) in PS, XFIG and Raster3D formats. The four
          structures were set with reference to the middle helical frame
          defined by blocks 1 and 11. Figures (c) and (d) have a small
          rotation about z-axis to make the helical axis vertical.

   p56figab p56a | p56b
   p56figcd p56c | p56d
     
[2] Figure 4.8 on page 78 of CRC & HD DNA book, Edition 2
   
   p78fig is a similar script as p56fig. The four structures were set with
   reference to the middle frame defined by blocks 11 and 12.

   p78fig p78a | p78b | p78c | p78d

[3] Negative propeller twist induced steric clash between purines in YR
    (pyrimidine-purine) dinucleotide steps

    see files: yr_clash.*

get_all combine all the above scripts to "get all".
