And here I'm again making math questions.

Currently (thanks to Zylann), I have a function that detects if a 2D line intersects with another. It works, with the exception of one situation: If the line is inside another while having the same angle (e. g. `(0, 0), (0, 100), (0, 50), (0, 150)`

), it will not treat it as an intersection.

Here is the current code:

```
func are_lines_intersecting(a, b, c, d):
var cd = d - c
var ab = b - a
var div = cd.y * ab.x - cd.x * ab.y
if abs(div) > 0.001:
var ac = a - c
var ua = ((cd.x * ac.y) - (cd.y * ac.x)) / div
if not ua >= 0.0 or not ua <= 1.0:
return false
var ub = ((ab.x * ac.y) - (ab.y * ac.x)) / div
if ub >= 0.0 and ub <= 1.0:
return true
return false
```