# constructing a genus 2 surface from 8-gon

I am requesting some help or reference for visualization?

I am having a hard time constructing a genus 2 surface from 8-gon. May I request for some reference? Here's the construction I used from Hatcher:

And here's my doodle.... I think I didn't get the identification of $b$ correctly at step (c), since I believe it $a$ shall go around the tube...

• One way is to "cheat", cutting the octagon diagonally, into two pieces, one with $c$ and $d$, the other with $a$ and $b$. Then each piece is a torus (minus a disk), and you can then glue them back together. – user641 Aug 29 '13 at 20:02
• Oh, that makes sense, @SteveD. Thank you. – 1LiterTears Aug 29 '13 at 20:08
• I know this thread is really old, but I've recently found a reference that has a very nice picture explaining how to make a double torus from an octagon by identifying opposite sides. Have a look at pages 137-138 of dx.doi.org/10.1016/0370-1573(86)90159-6 – Iordan Iordanov Apr 3 '17 at 10:02

Here are two visualizations. ${}{}{}{}{}{}{}{}{}{}$