Yes, that's the issue: the (thick) solid grey "major axis" lines on the background seemed to be a wire.

If I could make a recommendation, get rid of the grid lines entirely and only have 'dots' at regular spacing. Here's what Cadence Virtuoso looks like (the most popular circuit schematic tool for integrated circuit design):

https://www.eecs.umich.edu/courses/eecs311/f09/tutorials/cad...

consider a colorblind mode that uses patterns instead of colors for those of us that are color-challenged

the part that tripped me up is 0 showing in deep RED and I thought that meant I was doing something wrong. I came here, read this and realized I was actually right and then pressed the Run tests button and passed. This is a UX thing you'd want to address