I am making a factory game in Godot 4 and I am trying to have a scrolling effect of the arrows in corners (bent) belts.

For straight belts I am using this shader which works great, but how can I change it to support the bending?

shader_type canvas_item;

uniform vec2 speed = vec2(1.0, 0.0);

void fragment() {
    COLOR = texture(TEXTURE, mod(UV + TIME * speed, 1.0));
}