DD9 started with the mazes around 3yo before the math or organization part came in. Before her fine motor skills were adequate to complete them, she would look at the mazes and trace the path with her eyes.DH and I always laughed whenever we would go to a restaurant, because she would have the simple kids maze solved on the disposable place mat/menu before we would even sit down.
As far as the connection btw. math/mazes/order may be part of organizing ones brain. DD is a child who wants to make connections between information she already knows and how it relates to new information. It's like her own little filing system in her brain and all new information needs a place to go.
Also, when she is really interested in mazes (now that she's older, it comes and goes), she finds them everywhere. I can see the digestive system looking like a maze to your DS.
She also checked out a book on Mandalas in the library. She was tracing her fingers on the pictures as if she was solving a maze. DD has said that there is something soothing or meditative about a maze that she can't explain. This may be the fascination with HG kids whereas to another child it may be a frustrating challenge.
Jen