It's an artifact of how Rough.js renders sketchy lines. It does that by creating some random offsets. For some random values, it may create this effect for long lines, which is not ideal. This is less pronounced in shorter lines. The latest release has tried to reduce this effect, but there is a small probability that it may still happen: https://roughjs.com/posts/release-4.0/
It's how rough.js approximates hand-drawn sketchy lines. It looks great in some cases, okay in many others, but if they diverge too much, it looks weird. I think the intent is to evoke the style of sketching where everything is stroked multiple times with short lines.
Comments
What's the deal with lines that are composed of two lines with a space in the middle? This seems a very odd choice for something "hand drawn"
Eg: https://excalidraw.com/?id=5650452045627392
It's an artifact of how Rough.js renders sketchy lines. It does that by creating some random offsets. For some random values, it may create this effect for long lines, which is not ideal. This is less pronounced in shorter lines. The latest release has tried to reduce this effect, but there is a small probability that it may still happen: https://roughjs.com/posts/release-4.0/
It's how rough.js approximates hand-drawn sketchy lines. It looks great in some cases, okay in many others, but if they diverge too much, it looks weird. I think the intent is to evoke the style of sketching where everything is stroked multiple times with short lines.