hum… yeah if you don’t want any variable, you can just do :
(that’s not real programming down there)
while infinite do
turn (witouth going forward at the same time) on the right (90° or -90° i don’t remenber)
while there is black_line then
| turn left 90°
go forward (one square steps so maybe 50 steps? idk)
i think it works, but it can take a very long time