Step One:

Here's where I started with sourcing letterforms and architectural inspiration. R and G are both asymmetrical letters and H is symmetrical.  I feel like getting these three to mesh will be tough. 

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Step Two

I did a bunch of rough sketches and felt like I wasn't getting anywhere. Then I started to link two letters at a time: RG and RH to see how they fit together. Then I added the third letter back in and it got a lot better. I ended up picking two sketches with which to move forward into detailed sketches.

 

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Step Two (con't)

More sketching! I ended up with two tighter sketches to move forward with. I'm planning to add detail and flourish when I digitize. 

Feedback welcome!!