OpenGL and crawling ants

I'm having a flashback to 1985 when I took my first graphics programming class (We used this newish language called "C" and we worked on a VMS system).

One of the issues we needed to address in our project was the so called "crawling ants" problem. Thin lines that were slightly off the horizontal created patterns of being drawn for a bit, then not drawn, then drawn again. If you animated the scene (e.g., changing the camera's position), those on-and-off drawing patterns would move, looking like a line of ants crawling along a surface.

This last week I decided to take up programming on iOS, and I thought an OpenGL program would be fun.

I'm using GLKView with GLKBaseEffect and GLKTextureInfo to avoid writing my own shaders (Between Apple's SceneKit and Metal I feel a little strange spending time on OpenGL, but hey, you gotta start somewhere).

But guess what?

Crawling ants!

In theory the GLK texture should be doing linear sampling, and that should create a grayish color, not the constant flipping between black and white. I'm not seeing it though.

I wonder if I am doing something wrong?

The little dash lines move as I move through the scene creating a crawling ants feeling