I saw someone saying that you only need 3 road poneglyphs despite the plot/Nami saying you need 4. It got me thinking if it can be done and did a little bit of an analysis. I'm not sure if anyone's done this before but here it goes. So the way we find the location of Raftel is by getting the locations indicated by the road poneglyphs and finding where the two connecting lines intersect. If we know where the four points are, we know where the intersect is - where Raftel is. If we assume that the four points will be in a somewhat square/rectangle shape, technically you can find where the intersection will be if you only have 3 points. The intersection will lie anywhere between the line you have/can draw (line B-C in this example). This way, having only 3 road poneglyphs would do the job of finding Raftel if you search along that known line. However, having four points can result to any quadrilateral shape. This means it can be a bit skewed. You won't necessarily know where the fourth point's orientation is. Take this image for example. The 3 dark blue dots represent the 3 known points while the light blue dots represent any possible location of the fourth point location that will result in two lines intersecting. If you draw the intersections for each possibility, you will get this: As you can see above, the location of Raftel will lie anywhere in the perimeter of the triangle formed by the 3 known points. As we don't know the scale of how far apart these points are, we don't know how long it'll take to search the whole perimeter if we don't have the last point's location. Although it's possible to do, it's not plausible in my opinion. Although Raftel is at the end of the Grandline, we don't know if the road poneglyph locations are close to the end of the Grandline, or if the coordinates span the whole world - while ultimately intersecting somewhere at the end of the Grandline. This means traversing that triangular perimeter wouldn't exactly work and hence, requires the last road poneglyph. Of course, we don't know if there's any more to the road poneglyphs and the location of Raftel that Oda hasn't revealed yet. What do you guys think?