how to create multidigraph with string using eulerian circuits?

If we have C/G, AU/G ,C/U*AU ,AC/U/AU/AC/G, G/G/AC, G/AU, G/C as the middle part and the beginning start with AU and ends with CU. How can we make a Eulerian circuits? The "/" are option that it can be either C or G first and then next can either AU or G. If there is CU then we loop back to beginning AU hence the *. I honestly don't understand how i can possible create a graph out of this.

http://ift.tt/2joXJwX

Result :

AU C G AU G G AC U AU AC G CU
AU C G G AC U AU AC G AU G CU
AU G AU C G G AC U AU AC G CU
AU G G AC U AU AC G AU C G CU