1D3X:
reference: Solution structure of an intramolecular DNA triplex linked by hexakis(ethylene glycol) units: d(AGAGAGAA-(EG)6-TTCTCTCT-(EG)6-TCTCTCTT)., Tarkoy M, Phipps AK, Schultze P, Feigon J, Biochemistry 1998 Apr 28;37(17):5810-9. PMID: 9558314

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).