02:23:422 (1) - Every slider must have a clear and visible path of movement to follow from start to end. Sliders that overlap themselves without straightforward slider borders and sliders whose individual sections are unreadable cannot be used. A slider's end position must be clear under the assumption that a player has a skin which makes slider end circles fully transparent.
osu! ranking criteria
player won't understand how your slider works (for example he can go to the left instead of right)