withdraw indistinguishably into...

[blwings]

The super's eyes are two black lines that withdraw indistinguishably into the skein of his hieroglyphic squint.

This is from the Colson Whitehead's The Intuitionist. I'd like to check if I understood this sentence rightly. Does it mean that super's eyes look like two black lines because he squints until his eyes look like the skein and so it's difficult to read his mind? The most troubling part for me is "withdraw indistinguishably into". Please help me with this.

 

[jutfrank]

The narrator is describing what the super's eyes look like. It's hard to tell at what point his eyes stop and the lines that create the squint start.

You might imagine the eye of Horus rendered as an ancient Egyptian hieroglyph:

[link]